Basic Atomic Structure Worksheet ANSWERS

Basic Atomic Structure Worksheet ANSWERS

1a) protons b) neutronsc) electrons

a)Positive b) Neutral c) negative

2atomic number (or identity); charge

3 protons; electrons (in a neutral charge atom only!); same

4 average atomic weight; mass

5 mass number; nucleus

6neutrons; protons (or atomic number); mass number

7 Lithium = Li = 3Bromine = Br= 35

Iron = Fe=26Copper = Cu = 29

Oxygen = O = 8 Mercury = Hg = 80

Krypton = Kr = 36 Helium = He = 2

8 (A neutral atom by definition has NO charge! The protons and electrons are equal!)

Uranium = U = 92 Iodine = I = 53

Boron = B = 5 Xenon = Xe = 54

Chlorine = Cl = 17

9 NOTE****For these, I rounded the average atomic weight to the nearest whole number to get the mass number for the most abundant isotope. Mass number is the number of protons and neutrons: this number is not on the Periodic Table. Atomic weight is the average of all isotopes and this IS on the Periodic Table.

Barium = Ba = 137-56 = 81 Bismuth = Bi = 209-83 = 126

Carbon = C= 12-6 = 6 Hydrogen = H = 1-1 = 0

Fluorine = F = 19-9 = 10 Magnesium = Mg = 24-12 = 12

Europium = Eu = 152-63 = 89 Mercury = Hg = 201-80 = 121

10a.)Ironb.)Iodine c.) Helium d) Calcium e) Lead f) Hydrogen

11 a) YES b.) NO c) YES d) NO

12NOTE****For these, I rounded the average atomic weight to the nearest whole number to get the mass number for the most abundant isotope. Average Atomic Weight does not equal Mass Number. Tomorrow, I will either give you the mass number or you will have to figure it out by adding the protons and the neutrons

Z = Atomic Number (see structure packet)

A = Mass Number (see Structure packet)

For the isotopic symbol, the mass number is always written on the top left side of the element symbol. The atomic number is always written on the bottom left side of the element. The charge (if there is one) is written on the top right side. (see Structure packet!)

If no charge is given, assume that atom is neutral (equal protons and electrons).

If you are still struggling to remember all the definitions, make notecards or use this acronym that a colleague of mine (someone who taught many of you bio last year) uses.

“APE MAN”

APE is “Atomic Number = Protons = Electrons” (for neutral atoms only)

MAN is “Mass Number = Atomic Number – Neutrons”

NAME / Symbol / Z / A / protons / electrons / neutrons / Symbol
A / sodium / Na / 11 / 23 / 11 / 11 / 12 / 2311Na
B / chlorine / Cl / 17 / 35 / 17 / 18 / 18 / 3517Cl-1
C / potassium / K / 19 / 39 / 19 / 19 / 20 / 3919K
D / phosphorus / P / 15 / 31 / 15 / 15 / 16 / 3115P
E / iron / Fe / 26 / 56 / 26 / 24 / 30 / 5626Fe+2
F / iodine / I / 53 / 127 / 53 / 53 / 74 / 7453I
G / silver / Ag / 47 / 108 / 47 / 47 / 61 / 10847 Ag
H / krypton / Kr / 36 / 84 / 36 / 36 / 48 / 8436Kr
I / tungsten / W / 74 / 184 / 74 / 74 / 110 / 11074W
J / copper / Cu / 29 / 64 / 29 / 29 / 35 / 6429Cu
K / indium / In / 49 / 115 / 49 / 49 / 66 / 11549In
L / gold / Au / 79 / 197 / 79 / 78 / 118 / 19779Au+1
M / sulfur / S / 16 / 32 / 16 / 18 / 16 / 3216S-2