BIOLOGY: Introduction to Chemistry
MATTER has many forms, but all forms have two main properties:
(A) All matter occupies space, that is, it has volume
(B) All matter has mass. The amount of matter an object contains is called Mass.
1. Place an “X” by the substance which would be classified as matter:
_____rocks_____sunlight_____air_____water
_____humans_____heat_____plants_____nuclear radiation
_____animals_____chemicals_____gravity_____radio waves
THE STRUCTURE OF MATTER
An ATOM is the smallest whole part of a particular type of matter called an element and it has all of the properties of that element. Study the chart below on Atomic Structure.
SUBATOMICPARTICLE / SYMBOL / CHARGE / RELATIVE
MASS / LOCATION
1. PROTON / P / + / 1 / NUCLEUS
2. NEUTRON / n / O / 1 / NUCLEUS
3. ELECTRON / e / -- / 1/1800 / outside the nucleus
ATOMS
are composed
of three basic parts
2.What is the charge of the nucleus?______
3. Where is most of the mass of an atom found? ______
4.Under normal conditions, an atom is electrically neutral or uncharged since the number of positive ______in its nucleus is equal to the number of negative ______outside the nucleus.
5. When an atom has fewer electrons than protons, it has a ______charge.
6. For an atom to have a negative charge, it must have more ______than ______.
IONS
Under certain conditions an atom may lose or gain electrons is no longer neutral. When this happens, the atom is electrically charged and is known as an ION.
7. When an atom gains electrons and therefore, has more electrons than protons, the atom is known as a “positive” or “negative” ion. (circle)
8. When an atom loses electrons and, therefore, has fewer electrons than protons, the atom is known as a “negative” or “positive” ion. (circle)
Note: All types of matter can be classified into three (3) kinds according to their composition. The three types are (A) ELEMENTS (B) COMPOUNDS and (C) MIXTURES
ELEMENTS are pure substances which contain only one kind of atom and cannot be broken down into simpler substances by ordinary chemical means.
9. How many elements are listed on your Periodic Table of Elements? ______. Of these, how many are “Man-made?” (Look for the little “man” symbol in the box) ______and how many are naturally occurring? ______.
10. Each element is made up of the same three subatomic particles called: ______, ______, ______
11. The element “Iron” would have 26 protons, ______, and 30 neutrons.
Different types of the same atom are called ISOTOPES. Isotopes of the same atom differ only in the number of neutrons in the nucleus. For example, one isotope you have heard about previously is Carbon-14 (a radioactive isotope of Carbon-14 used to date fossils.) It has 6 protons, 6 electrons, and 6 neutrons.
12. Isotopes differ from the usual form of the element in the number of ______they contain.
Look again at your Periodic Table. These “letter” symbols are called ATOMIC SYMBOLS and are a chemical shorthand used to name and write about atoms and elements.
13. Match the Atomic Symbol for these 13 elements with their full names listed below:
____ Carbon ____ Hydrogen ____ Oxygen ____ Phosphorus ____ Potassium
____ Iodine ____ Nitrogen ____ Sulfur ____ Calcium ____ Iron
____ Magnesium ____ Sodium ____ Chlorine
Remember “CHOPKINSCaFeMighty good Salt” Table salt = sodium chloride = NaCl
ATOMIC NUMBER is assigned to every atom. This number is listed above the Atomic Symbol on the Periodic Table. The atomic number of the element is the number of protons in the nucleus of atom of that element. Since an atom has the same number of electrons as protons, the atomicnumber is also the same as the number of electrons around the nucleus.
14. Sodium has an atomic number of 11 it therefore has _____ protons and _____ electrons per atom.
ATOMIC WEIGHTAll atoms have weight even though the weight is hard to measure because of the atom’s small size. The weight of an atom is called ‘Atomic Weight” and is found below the atomic symbol of the periodic table. Since the greatest mass of an atom is found in the nucleus, the atomic weight is based on the number of neutrons and protons in the nucleus of the atom. Thus, the Atomic Weight of an element = the # of protons + # of Neutrons
Answer the questions below for the element shown to the left
15. Name this element ______
16. How many atoms does this Atomic Symbol represent ______
17. What is this element’s atomic number? ______
18. What is this element’s atomic weight? ______
19. How many protons are found in one atom of this element? _____ How many electrons are found in one atom of this element? _____ How many neutrons? _____
STATES OF MATTER
Most elements exist as a SOLID, or a GAS. Very few are found as LIQUIDS
20. Give the Atomic Symbol for 3 gasses_____, _____, _____ and 1 liquid element _____
MOLECULES AND COMPOUNDS Many of the substances you see around you are not made of just one element. Substances that are formed by the chemical combinations of two or more different kinds of elements in definite proportions by weight are called COMPOUNDS. The smallest part of a compound having all the properties of the substance is a MOLECULE. Molecules may be made up of the same kinds of atoms or different kinds of atoms. When the atoms of different elements combine chemically, the compound formed has new properties or characteristics.
The chemist’s shorthand or abbreviation for a compound is called a MOLECULAR FORMULA
21. Using your textbook, write out the molecular formulas for the following:
Hydrogen gas ______Glucose sugar ______
Water ______Ammonia ______
Chlorophyll A ______Ethyl Alcohol C2H5OH_____(example)
22. Which of the molecules listed above is an element and NOT a compound? ______
23. How many atoms make up a water molecules? ______a glucose molecule? ______
How many atoms make up the “Chlorophyll-A” molecule? ______
24. How many different elements make up a chlorophyll molecule? ______
MIXTURES When elements or compounds are physically combined (not by chemical combination), the resulting kind of matter is called a MIXTURE. The elements or compounds which make up a mixture keep their own properties.
25. The following combinations are mixtures:
Salt and Pepper……..Oil and Water…….Soil….
List two other examples:
______and ______
- 1 -