Miscellaneous and Helpful Information for NICET Fire Alarm System Certification Testing

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Miscellaneous and Helpful Information for NICET Fire Alarm System Certification Testing

Pencil Hardness

Calculating Volume

Volume Formulas

Units

Surface Area Formulas

Definitions Related to Circles

Circumference of Circle

Area of Circle:

Length of a Circular Arc:

Area of Circle Sector:

Equation of Circle: (Cartesian coordinates)

Equation of Circle: (polar coordinates)

Equation of a Circle: (parametric coordinates)

The Right Triangle

Table of Elements

Element Descriptions

WEIGHT AND MEASURESTables

Grammar

Sentence Structure

The Simple Sentence

The Compound Sentence

Special Cases of Compound Sentences

The Complex Sentence

The Loose Sentence

The Periodic Sentence

The Declarative Sentence

The Interrogative Sentence

The Rhetorical Question

The Exclamatory Sentence

The Imperative Sentence

Participles

Infinitives

Gerunds

PUNCTUATION

THE COMMA:

THE SEMICOLON:

THE COLON:

THE DASH:

THE HYPHEN:

QUOTATION MARKS:

Punctuation Practice Exercise

Punctuation Practice Test Answers

Miscellaneous and Helpful Information for NICET Fire Alarm System Certification Testing

Pencil Hardness

The 'H' stands for hardness, the 'B' stands for blackness, and HB is for hard and black pencils. The hardest is a 9H, followed by 8H, 7H, 6H, 5H, 4H, 3H, 2H, and H. F is the middle of the hardness scale; then comes HB, B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, and 9B, which is the softest. Another grading method uses numbers; the equivalents would be #1=B, #2=HB, #2-1/2=F, #3=H, and #4=2H. The most commonly used writing pencil is the #2 (HB grade), which is fairly soft, contains more graphite, and leaves a dark mark.

Calculating Volume

(pi = = 3.141592...)

Volume Formulas

Note: "ab" means "a" multiplied by "b". "a2" means "a squared", which is the same as "a" times "a". "b3" means "b cubed", which is the same as "b" times "b" times "b".

Be careful!! Units count. Use the same units for all measurements.

Examples

cube = a 3

rectangular prism = a b c

irregular prism = b h

cylinder = b h = pi r 2 h

pyramid = (1/3) b h

cone = (1/3) b h = 1/3 pi r 2 h

sphere = (4/3) pi r 3

ellipsoid = (4/3) pi r1 r2 r3

Units

Area is measured in "cubic" units. The volume of a figure is the number of cubes required to fill it completely, like blocks in a box.

Volume of a cube = side times side times side. Since each side of a square is the same, it can simply be the length of one side cubed.

If a square has one side of 4 inches, the area would be 4 inches times 4 inches times 4 inches, or 64 cubic inches. (Cubic inches can also be written in3.)

Be sure to use the same units for all measurements. You cannot multiply feet times inches times yards, it doesn't make a perfectly cubed measurement.

The volume of a rectangular prism is the length on the side times the width times the height. If the width is 4 inches, the length is 1 foot and the height is 3 feet, what is the volume?

NOT CORRECT .... 4 times 1 times 3 = 12

CORRECT.... 4 inches is the same as 1/3 feet. Volume is 1/3 feet times 1 foot times 3 feet = 1 cubic foot (or 1 cu. ft., or 1 ft3).

Surface Area Formulas
In general, the surface area is the sum of all the areas of all the shapes that cover the surface of the object.

Note: "ab" means "a" multiplied by "b". "a2" means "a squared", which is the same as "a" times "a".

Be careful!! Units count. Use the same units for all measurements.

Examples

Surface Area of a Cube = 6 a 2

(a is the length of the side of each edge of the cube)

In words, the surface area of a cube is the area of the six squares that cover it. The area of one of them is a*a, or a 2 . Since these are all the same, you can multiply one of them by six, so the surface area of a cube is 6 times one of the sides squared.

Surface Area of a Rectangular Prism = 2ab + 2bc + 2ac

(a, b, and c are the lengths of the 3 sides)

In other words, the surface area of a rectangular prism is the are of the six rectangles that cover it. But we don't have to figure out all six because we know that the top and bottom are the same, the front and back are the same, and the left and right sides are the same.

The area of the top and bottom (side lengths a and c) = a*c. Since there are two of them, you get 2ac. The front and back have side lengths of b and c. The area of one of them is b*c, and there are two of them, so the surface area of those two is 2bc. The left and right side have side lengths of a and b, so the surface area of one of them is a*b. Again, there are two of them, so their combined surface area is 2ab.

Surface Area of Any Prism

(b is the shape of the ends)

Surface Area = Lateral area + Area of two ends

(Lateral area) = (perimeter of shape b) * L

Surface Area = (perimeter of shape b) * L+ 2*(Area of shape b)

Surface Area of a Sphere = 4 pi r 2

(r is radius of circle)

Surface Area of a Cylinder = 2 pi r 2 + 2 pi r h

(h is the height of the cylinder, r is the radius of the top)

Surface Area = Areas of top and bottom +Area of the side

Surface Area = 2(Area of top) + (perimeter of top)* height

Surface Area = 2(pi r 2) + (2 pi r)* h

In words, the easiest way is to think of a can. The surface area is the areas of all the parts needed to cover the can. That's the top, the bottom, and the paper label that wraps around the middle.

You can find the area of the top (or the bottom). That's the formula for area of a circle (pir2). Since there is both a top and a bottom, that gets multiplied by two.

The side is like the label of the can. If you peel it off and lay it flat it will be a rectangle. The area of a rectangle is the product of the two sides. One side is the height of the can, the other side is the perimeter of the circle, since the label wraps once around the can. So the area of the rectangle is (2 pi r)* h.

Add those two parts together and you have the formula for the surface area of a cylinder.

Surface Area = 2(pi r 2) + (2 pi r)* h

Tip! Don't forget the units.

These equations will give you correct answers if you keep the units straight. For example - to find the surface area of a cube with sides of 5 inches, the equation is:

Surface Area = 6*(5 inches)2

= 6*(25 square inches)

= 150 sq. inches

Definitions Related to Circles

arc: a curved line that is part of the circumference of a circle
chord: a line segment within a circle that touches 2 points on the circle.
circumference: the distance around the circle.
diameter: the longest distance from one end of a circle to the other.
origin: the center of the circle
pi (): A number, 3.141592..., equal to (the circumference) / (the diameter) of any circle.
radius: distance from center of circle to any point on it.
sector: is like a slice of pie (a circle wedge).
tangent of circle: a line perpendicular to the radius that touches ONLY one point on the circle.

Diameter = 2 x radius of circle

Circumference of Circle = PI x diameter = 2 PI x radius
where PI = = 3.141592...

Area of Circle:
area = PI r2

Length of a Circular Arc: (with central angle )
if the angle is in degrees, then length = x (PI/180) x r
if the angle is in radians, then length = r x

Area of Circle Sector: (with central angle )
if the angle is in degrees, then area = (/360)x PI r2
if the angle is in radians, then area = ((/(2PI))x PI r2

Equation of Circle: (Cartesian coordinates)

for a circle with center (j, k) and radius (r):
(x-j)^2 + (y-k)^2 = r^2

Equation of Circle: (polar coordinates)
for a circle with center (0, 0): r() = radius

for a circle with center with polar coordinates: (c, ) and radius a:
r2 - 2cr cos( - ) + c2 = a2

Equation of a Circle: (parametric coordinates)
for a circle with origin (j, k) and radius r:
x(t) = r cos(t) + j y(t) = r sin(t) + k

The Right Triangle

The right triangle is one of the most important geometrical figures, used in many applications for thousands of years.

A Greek mathematician named Pythagoras developed a formula, called the Pythagorean Theorem, for finding the lengths of the sides of any right triangle. He treated each side of a right triangle as though it were a square and discovered that the total area of the two smaller squares is equal to the area of the largest square. He wrote this discovery as a formula:

where c is the hypotenuse and a and b are the other two legs of the triangle. Move your mouse over the triangle to learn more.

A right triangle has one angle equal to 90 degrees. A right triangle can also be an isosceles triangle--which means that it has two sides that are equal. A right isosceles triangle has a 90-degree angle and two 45-degree angles. This is the only right triangle that is an isosceles triangle. This version of the right triangle is so popular that plastic models of them are manufactured and used by architects, engineers, carpenters, and graphic artists in their design and construction work.

Another interesting right triangle is the 30-60-90 degree triangle. The ratio of this triangle's longest side to its shortest side is "two to one." That is, the longest side is twice as long as the shortest side. It too is manufactured in plastic and widely used in design, drawing, and building applications.

You can find an endless number of examples of right triangles. One of the most famous is the "3, 4, 5 triangle."

The Egyptians used this triangle for land surveying. Some believe that they also used it to help design their pyramids. Whether they did or not, the 3-4-5 triangle is still used by surveyors. Carpenters and woodworkers also use it to make their corners square.

Pythagoras was a Greek mathematician who lived about 2500 years ago, and who developed the most famous formula in geometry, possibly in all of mathematics! He proved that, for a right triangle, the sum of the squares of the two sides that join at a right angle equals the square of the third side. The third side--the side opposite the right angle--is called the hypotenuse of the right triangle. The two shorter sides are usually called "legs."

This formula is called the Pythagorean Theorem in honor of Pythagoras. It is usually written as the equation below, where a and b are the measures of the legs of the triangle and c is the measure of the hypotenuse.

Let's try out the Pythagorean Theorem using this right triangle with sides of 5 and 12 cm, and a hypotenuse of 13 cm. We can verify that the Pythagorean Theorem is true by substituting in the values. The square root of 169 is 13, which is the measure of the hypotenuse in this triangle.

The Pythagorean Theorem has many uses. You can use it to verify whether or not a triangle is a right triangle. Or you can use it to find the missing measures of sides. Let's use the Pythagorean Theorem to find the missing measure of the leg of the right triangle SAM.

Substitute the values into the formula and perform the calculations, like this. We find that the square of the hypotenuse, or c squared, is equal to 400. To find c, we take the square root of 400, which is 20. This is the value we're looking for, the missing measure of the leg,

Table of Elements

Element Descriptions

# / Atomic
Weight / Name / Symbol / M.P.
( °C ) / B.P.
( °C ) / Density*
(g/cm3) / Earth crust
( % )* / Discovery
(Year) / Group* / Electron
configuration
1 / 1.0079 / Hydrogen / H / -259 / -253 / 0.09 / 0.14 / 1776 / 1 / 1s1
2 / 4.0026 / Helium / He / -272 / -269 / 0.18 / 1895 / 18 / 1s2
3 / 6.941 / Lithium / Li / 180 / 1347 / 0.53 / 1817 / 1 / [He] 2s1
4 / 9.0122 / Beryllium / Be / 1278 / 2970 / 1.85 / 1797 / 2 / [He] 2s2
5 / 10.811 / Boron / B / 2300 / 2550 / 2.34 / 1808 / 13 / [He] 2s2 2p1
6 / 12.0107 / Carbon / C / 3500 / 4827 / 2.26 / 0.094 / ancient / 14 / [He] 2s2 2p2
7 / 14.0067 / Nitrogen / N / -210 / -196 / 1.25 / 1772 / 15 / [He] 2s2 2p3
8 / 15.9994 / Oxygen / O / -218 / -183 / 1.43 / 46.71 / 1774 / 16 / [He] 2s2 2p4
9 / 18.9984 / Fluorine / F / -220 / -188 / 1.7 / 0.029 / 1886 / 17 / [He] 2s2 2p5
10 / 20.1797 / Neon / Ne / -249 / -246 / 0.9 / 1898 / 18 / [He] 2s2 2p6
11 / 22.9897 / Sodium / Na / 98 / 883 / 0.97 / 2.75 / 1807 / 1 / [Ne] 3s1
12 / 24.305 / Magnesium / Mg / 639 / 1090 / 1.74 / 2.08 / 1755 / 2 / [Ne] 3s2
13 / 26.9815 / Aluminum / Al / 660 / 2467 / 2.7 / 8.07 / 1825 / 13 / [Ne] 3s2 3p1
14 / 28.0855 / Silicon / Si / 1410 / 2355 / 2.33 / 27.69 / 1824 / 14 / [Ne] 3s2 3p2
15 / 30.9738 / Phosphorus / P / 44 / 280 / 1.82 / 0.13 / 1669 / 15 / [Ne] 3s2 3p3
16 / 32.065 / Sulfur / S / 113 / 445 / 2.07 / 0.052 / ancient / 16 / [Ne] 3s2 3p4
17 / 35.453 / Chlorine / Cl / -101 / -35 / 3.21 / 0.045 / 1774 / 17 / [Ne] 3s2 3p5
18 / 39.948 / Argon / Ar / -189 / -186 / 1.78 / 1894 / 18 / [Ne] 3s2 3p6
19 / 39.0983 / Potassium / K / 64 / 774 / 0.86 / 2.58 / 1807 / 1 / [Ar] 4s1
20 / 40.078 / Calcium / Ca / 839 / 1484 / 1.55 / 3.65 / 1808 / 2 / [Ar] 4s2
21 / 44.9559 / Scandium / Sc / 1539 / 2832 / 2.99 / 1879 / 3 / [Ar] 3d1 4s2
22 / 47.867 / Titanium / Ti / 1660 / 3287 / 4.54 / 0.62 / 1791 / 4 / [Ar] 3d2 4s2
23 / 50.9415 / Vanadium / V / 1890 / 3380 / 6.11 / 1830 / 5 / [Ar] 3d3 4s2
24 / 51.9961 / Chromium / Cr / 1857 / 2672 / 7.19 / 0.035 / 1797 / 6 / [Ar] 3d5 4s1
25 / 54.938 / Manganese / Mn / 1245 / 1962 / 7.43 / 0.09 / 1774 / 7 / [Ar] 3d5 4s2
26 / 55.845 / Iron / Fe / 1535 / 2750 / 7.87 / 5.05 / ancient / 8 / [Ar] 3d6 4s2
27 / 58.9332 / Cobalt / Co / 1495 / 2870 / 8.9 / 1735 / 9 / [Ar] 3d7 4s2
28 / 58.6934 / Nickel / Ni / 1453 / 2732 / 8.9 / 0.019 / 1751 / 10 / [Ar] 3d8 4s2
29 / 63.546 / Copper / Cu / 1083 / 2567 / 8.96 / ancient / 11 / [Ar] 3d10 4s1
30 / 65.39 / Zinc / Zn / 420 / 907 / 7.13 / ancient / 12 / [Ar] 3d10 4s2
31 / 69.723 / Gallium / Ga / 30 / 2403 / 5.91 / 1875 / 13 / [Ar] 3d10 4s2 4p1
32 / 72.64 / Germanium / Ge / 937 / 2830 / 5.32 / 1886 / 14 / [Ar] 3d10 4s2 4p2
33 / 74.9216 / Arsenic / As / 81 / 613 / 5.72 / ancient / 15 / [Ar] 3d10 4s2 4p3
34 / 78.96 / Selenium / Se / 217 / 685 / 4.79 / 1817 / 16 / [Ar] 3d10 4s2 4p4
35 / 79.904 / Bromine / Br / -7 / 59 / 3.12 / 1826 / 17 / [Ar] 3d10 4s2 4p5
36 / 83.8 / Krypton / Kr / -157 / -153 / 3.75 / 1898 / 18 / [Ar] 3d10 4s2 4p6
37 / 85.4678 / Rubidium / Rb / 39 / 688 / 1.63 / 1861 / 1 / [Kr] 5s1
38 / 87.62 / Strontium / Sr / 769 / 1384 / 2.54 / 1790 / 2 / [Kr] 5s2
39 / 88.9059 / Yttrium / Y / 1523 / 3337 / 4.47 / 1794 / 3 / [Kr] 4d1 5s2
40 / 91.224 / Zirconium / Zr / 1852 / 4377 / 6.51 / 0.025 / 1789 / 4 / [Kr] 4d2 5s2
41 / 92.9064 / Niobium / Nb / 2468 / 4927 / 8.57 / 1801 / 5 / [Kr] 4d4 5s1
42 / 95.94 / Molybdenum / Mo / 2617 / 4612 / 10.22 / 1781 / 6 / [Kr] 4d5 5s1
43 / * / 98 / Technetium / Tc / 2200 / 4877 / 11.5 / 1937 / 7 / [Kr] 4d5 5s2
44 / 101.07 / Ruthenium / Ru / 2250 / 3900 / 12.37 / 1844 / 8 / [Kr] 4d7 5s1
45 / 102.9055 / Rhodium / Rh / 1966 / 3727 / 12.41 / 1803 / 9 / [Kr] 4d8 5s1
46 / 106.42 / Palladium / Pd / 1552 / 2927 / 12.02 / 1803 / 10 / [Kr] 4d10
47 / 107.8682 / Silver / Ag / 962 / 2212 / 10.5 / ancient / 11 / [Kr] 4d10 5s1
48 / 112.411 / Cadmium / Cd / 321 / 765 / 8.65 / 1817 / 12 / [Kr] 4d10 5s2
49 / 114.818 / Indium / In / 157 / 2000 / 7.31 / 1863 / 13 / [Kr] 4d10 5s2 5p1
50 / 118.71 / Tin / Sn / 232 / 2270 / 7.31 / ancient / 14 / [Kr] 4d10 5s2 5p2
51 / 121.76 / Antimony / Sb / 630 / 1750 / 6.68 / ancient / 15 / [Kr] 4d10 5s2 5p3
52 / 127.6 / Tellurium / Te / 449 / 990 / 6.24 / 1783 / 16 / [Kr] 4d10 5s2 5p4
53 / 126.9045 / Iodine / I / 114 / 184 / 4.93 / 1811 / 17 / [Kr] 4d10 5s2 5p5
54 / 131.293 / Xenon / Xe / -112 / -108 / 5.9 / 1898 / 18 / [Kr] 4d10 5s2 5p6
55 / 132.9055 / Cesium / Cs / 29 / 678 / 1.87 / 1860 / 1 / [Xe] 6s1
56 / 137.327 / Barium / Ba / 725 / 1140 / 3.59 / 0.05 / 1808 / 2 / [Xe] 6s2
57 / 138.9055 / Lanthanum / La / 920 / 3469 / 6.15 / 1839 / 3 / [Xe] 5d1 6s2
58 / 140.116 / Cerium / Ce / 795 / 3257 / 6.77 / 1803 / 101 / [Xe] 4f1 5d1 6s2
59 / 140.9077 / Praseodymium / Pr / 935 / 3127 / 6.77 / 1885 / 101 / [Xe] 4f3 6s2
60 / 144.24 / Neodymium / Nd / 1010 / 3127 / 7.01 / 1885 / 101 / [Xe] 4f4 6s2
61 / * / 145 / Promethium / Pm / 1100 / 3000 / 7.3 / 1945 / 101 / [Xe] 4f5 6s2
62 / 150.36 / Samarium / Sm / 1072 / 1900 / 7.52 / 1879 / 101 / [Xe] 4f6 6s2
63 / 151.964 / Europium / Eu / 822 / 1597 / 5.24 / 1901 / 101 / [Xe] 4f7 6s2
64 / 157.25 / Gadolinium / Gd / 1311 / 3233 / 7.9 / 1880 / 101 / [Xe] 4f7 5d1 6s2
65 / 158.9253 / Terbium / Tb / 1360 / 3041 / 8.23 / 1843 / 101 / [Xe] 4f9 6s2
66 / 162.5 / Dysprosium / Dy / 1412 / 2562 / 8.55 / 1886 / 101 / [Xe] 4f10 6s2
67 / 164.9303 / Holmium / Ho / 1470 / 2720 / 8.8 / 1867 / 101 / [Xe] 4f11 6s2
68 / 167.259 / Erbium / Er / 1522 / 2510 / 9.07 / 1842 / 101 / [Xe] 4f12 6s2
69 / 168.9342 / Thulium / Tm / 1545 / 1727 / 9.32 / 1879 / 101 / [Xe] 4f13 6s2
70 / 173.04 / Ytterbium / Yb / 824 / 1466 / 6.9 / 1878 / 101 / [Xe] 4f14 6s2
71 / 174.967 / Lutetium / Lu / 1656 / 3315 / 9.84 / 1907 / 101 / [Xe] 4f14 5d1 6s2
72 / 178.49 / Hafnium / Hf / 2150 / 5400 / 13.31 / 1923 / 4 / [Xe] 4f14 5d2 6s2
73 / 180.9479 / Tantalum / Ta / 2996 / 5425 / 16.65 / 1802 / 5 / [Xe] 4f14 5d3 6s2
74 / 183.84 / Tungsten / W / 3410 / 5660 / 19.35 / 1783 / 6 / [Xe] 4f14 5d4 6s2
75 / 186.207 / Rhenium / Re / 3180 / 5627 / 21.04 / 1925 / 7 / [Xe] 4f14 5d5 6s2
76 / 190.23 / Osmium / Os / 3045 / 5027 / 22.6 / 1803 / 8 / [Xe] 4f14 5d6 6s2
77 / 192.217 / Iridium / Ir / 2410 / 4527 / 22.4 / 1803 / 9 / [Xe] 4f14 5d7 6s2
78 / 195.078 / Platinum / Pt / 1772 / 3827 / 21.45 / 1735 / 10 / [Xe] 4f14 5d9 6s1
79 / 196.9665 / Gold / Au / 1064 / 2807 / 19.32 / ancient / 11 / [Xe] 4f14 5d10 6s1
80 / 200.59 / Mercury / Hg / -39 / 357 / 13.55 / ancient / 12 / [Xe] 4f14 5d10 6s2
81 / 204.3833 / Thallium / Tl / 303 / 1457 / 11.85 / 1861 / 13 / [Xe] 4f14 5d10 6s2 6p1
82 / 207.2 / Lead / Pb / 327 / 1740 / 11.35 / ancient / 14 / [Xe] 4f14 5d10 6s2 6p2
83 / 208.9804 / Bismuth / Bi / 271 / 1560 / 9.75 / ancient / 15 / [Xe] 4f14 5d10 6s2 6p3
84 / * / 209 / Polonium / Po / 254 / 962 / 9.3 / 1898 / 16 / [Xe] 4f14 5d10 6s2 6p4
85 / * / 210 / Astatine / At / 302 / 337 / 1940 / 17 / [Xe] 4f14 5d10 6s2 6p5
86 / * / 222 / Radon / Rn / -71 / -62 / 9.73 / 1900 / 18 / [Xe] 4f14 5d10 6s2 6p6
87 / * / 223 / Francium / Fr / 27 / 677 / 1939 / 1 / [Rn] 7s1
88 / * / 226 / Radium / Ra / 700 / 1737 / 5.5 / 1898 / 2 / [Rn] 7s2
89 / * / 227 / Actinium / Ac / 1050 / 3200 / 10.07 / 1899 / 3 / [Rn] 6d1 7s2
90 / 232.0381 / Thorium / Th / 1750 / 4790 / 11.72 / 1829 / 102 / [Rn] 6d2 7s2
91 / 231.0359 / Protactinium / Pa / 1568 / 15.4 / 1913 / 102 / [Rn] 5f2 6d1 7s2
92 / 238.0289 / Uranium / U / 1132 / 3818 / 18.95 / 1789 / 102 / [Rn] 5f3 6d1 7s2
93 / * / 237 / Neptunium / Np / 640 / 3902 / 20.2 / 1940 / 102 / [Rn] 5f4 6d1 7s2
94 / * / 244 / Plutonium / Pu / 640 / 3235 / 19.84 / 1940 / 102 / [Rn] 5f6 7s2
95 / * / 243 / Americium / Am / 994 / 2607 / 13.67 / 1944 / 102 / [Rn] 5f7 7s2
96 / * / 247 / Curium / Cm / 1340 / 13.5 / 1944 / 102
97 / * / 247 / Berkelium / Bk / 986 / 14.78 / 1949 / 102
98 / * / 251 / Californium / Cf / 900 / 15.1 / 1950 / 102
99 / * / 252 / Einsteinium / Es / 860 / 1952 / 102
100 / * / 257 / Fermium / Fm / 1527 / 1952 / 102
101 / * / 258 / Mendelevium / Md / 1955 / 102
102 / * / 259 / Nobelium / No / 827 / 1958 / 102
103 / * / 262 / Lawrencium / Lr / 1627 / 1961 / 102
104 / * / 261 / Rutherfordium / Rf / 1964 / 4
105 / * / 262 / Dubnium / Db / 1967 / 5
106 / * / 266 / Seaborgium / Sg / 1974 / 6
107 / * / 264 / Bohrium / Bh / 1981 / 7
108 / * / 277 / Hassium / Hs / 1984 / 8
109 / * / 268 / Meitnerium / Mt / 1982 / 9

Abbreviations and Definitions:
No. - Atomic Number
M.P. - melting point
B.P. - boiling point
* Density of elements with boiling points below 0°C is given in g/l
* Earth crust composition average values are from a report by F. W. Clarke and H. S. Washington, 1924. Elemental composition of crustal rocks differ between different localities (see article).
* Group: There are only 18 groups in the periodic table that constitute the columns of the table. Lanthanoids and Actinoids are numbered as 101 and 102 to separate them in sorting by group.

Atomic number: The number of protons in an atom. Each element is uniquely defined by its atomic number.

Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, 12C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass of about 1 amu.

Isotope: Atoms of the same element with the same atomic number, but different number of neutrons. Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. Elements have more than one isotope with varying numbers of neutrons. For example, there are two common isotopes of carbon, 12C and 13C which have 6 and 7 neutrons respectively. The abundances of different isotopes of elements vary in nature depending on the source of materials. For relative abundances of isotopes in nature see reference on Isotopic Composition of the Elements.

Atomic weight: Atomic weight values represent weighted average of the masses of all naturally occurring isotopes of an element. The values shown here are based on the IUPAC Commission determinations (Pure Appl. Chem. 73:667-683, 2001). The elements marked with an asterisk have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Electron configuration: The distribution of electrons according to the energy sublevels (subshells) in uncharged atoms. The noble gas shown in square brackets (e.g. [He]), marks that all the subshells associated with that element are fully occupied by electrons. For further information see another web site.

Energy levels and sublevels
Principal energy level
(Quantum number: n) / Sublevels available
(Quantum number: l)
1
2
3
4
5
6 / 1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f 5g
6s 6p 6d 6f 6g 6h

Ionization energy (IE): The energy required to remove the outermost electron from an atom or a positive ion in its ground level. The table lists only the first IE in eV units. To convert to kJ/mol multiply by 96.4869. Reference: NIST Reference Table on Ground levels and ionization energies for the neutral atoms. IE decreases going down a column of the periodic table, and increases from left to right in a row. Thus, alkali metals have the lowest IE in a period and Rare gases have the highest.

WEIGHT AND MEASURESTables

WEIGHT AND MEASURES1
UNIT / ABBREVIATION
OR SYMBOL / EQUIVALENTS IN OTHER
UNITS OF SAME SYSTEM / METRIC EQUIVALENT
WEIGHT
Avoirdupois2
ton
short ton / 20 short hundredweight, 2000 pounds / 0.907 metric ton
long ton / 20 long hundredweight, 2240 pounds / 1.016 metric ton
hundredweight / cwt
short hundredweight / 100 pounds, 0.05 short tons / 45.359 kilograms
long hundredweight / 112 pounds, 0.05 long ton / 50.802 kilograms
pound / lb or lb avdp
also # / 16 ounces, 7000 grains / 0.454 kilogram
ounce / oz or oz avdp / 16 drams, 437.5 grains, 0.0625 pound / 28.350 grams
dram / dr or dr avdp / 27.344 grains, 0.0625 ounce / 1.772 grams
grain / gr / 0.037 dram, 0.002286 ounce / 0.0648 gram
Troy
pound / lb t / 12 ounces, 240 pennyweight, 5760 grains / 0.373 kilogram
ounce / oz t / 20 pennyweight, 480 grains, 0.083 pound / 31.103 grams
pennyweight / dwt also pwt / 24 grains, 0.05 ounce / 1.555 grams
grain / gr / 0.042 pennyweight, 0.002083 ounce / 0.0648 gram
Apothecaries'
pound / lb ap / 12 ounces, 5760 grains / 0.373 kilogram
ounce / oz ap / 8 drams, 480 grains, 0.083 pound / 31.103 grams
dram / dr ap / 3 scruples, 60 grains / 3.888 grams
scruple / s ap / 20 grains, 0.333 dram / 1.296 grams
grain / gr / 0.05 scruple, 0.002083 ounce, 0.0166 dram / 0.0648 gram
CAPACITY
U.S. liquid measure
gallon / gal / 4 quarts (231 cubic inches) / 3.785 liters
quart / qt / 2 pints (57.75 cubic inches) / 0.946 liter
pint / pt / 4 gills (28.875 cubic inches / 473.176 milliliters
gill / gi / 4 fluid ounces (7.219 cubic inches) / 118.294 milliliters
fluid ounce / fl oz / 8 fluid drams (1.805) cub inches) / 29.573 milliliters
fluid dram / fl dr / 60 minims (0.226 cubic inch) / 3.697 milliliters
minim / min / 1/60 fluid dram (0.003760 cubic inch) / 0.061610 milliliter
U.S. dry measure
bushel / bu / 4 pecks (2150.42 cubic inches) / 35.239 liters
peck / pk / 8 quarts (537.605 cubic inches) / 8.810 liters
quart / qt / 2 pints (67.201 cubic inches) / 1.101 liters
pint / pt / ½ quart (33.600 cubic inches) / 0.551 liter
British imperial liquid and dry measure
bushel / bu / 4 pecks (2219.36 cubic inches) / 36.369 liters
peck / pk / 2 gallons (554.84 cubic inches) / 9.092 liters
gallon / gal / 4 quarts (277.420 cubic inches) / 4.546 liters
quart / qt / 2 pints (69.355 cubic inches) / 1.136 liters
pint / pt / 4 gills (34.678 cubic inches) / 568.26 milliliters
gill / gi / 5 fluid ounces (8.669 cubic inches) / 142.066 milliliters
fluid ounce / fl oz / 8 fluid drams (1.7339 cubic inches) / 28.412 milliliters
fluid dram / fl dr / 60 minims (0.216734 cubic inch) / 3.5516 milliliters
minim / min / 1/60 fluid dram (0.003612 cubic inch) / 0.059194 milliliter
LENGTH
mile / mi / 5280 feet, 1760 yards, 320 rods / 1.609 kilometers
rod / rd / 5.50 yards, 16.5 feet / 5.029 meters
yard / yd / 3 feet, 36 inches / 0.9144 meter
foot / ft or ' / 12 inches, 0.333 yard / 30.48 centimeters
inch / in or " / 0.083 foot, 0.028 yard / 2.54 centimeters
AREA
square mile / sq mi or mi2 / 640 acres, 102,400 square rods / 2.590 square kilometers
acre / 4840 square yards, 43,560 square feet / 0.405 hectare, 4047 square meters
square rod / sq rd or rd2 / 30.25 square yards, 0.00625 acre / 25.293 square meters
square yard / sq yd or yd2 / 1296 square inches, 9 square feet / 0.836 square meter
square foot / sq ft or ft2 / 144 square inches, 0.111 square yard / 0.093 square meter
square inch / sq in or in2 / 0.0069 square foot, 0.00077 square yard / 6.452 square centimeters
VOLUME
cubic yard / cu yd or yd3 / 27 cubic feet, 46,656 cubic inches / 0.765 cubic meter
cubic foot / cu ft or ft3 / 1728 cubic inches, 0.0370 cubic yard / 0.028 cubic meter
cubic inch / cu in or in3 / 0.00058 cubic foot, 0.000021 cubic yard / 16.387 cubic centimeters

1For U.S. equivalents of the metric unit see Metric System table.
2The U.S. uses the avoirdupois units as a common system of measuring weight.