Name: _________________________________________________________________ Period: _______
Unit 1: Basic Chemistry For Biology
Activity 2: Composition of Matter Practice Problems pt. 2
Vocabulary Practice
____1. Compound
a. Formed when an electron is given from one atom
to another
____2. Stable atom
b. A pure substance made of two or more elements
____3. Covalent Bond
c. An atom that has a full outer energy shell
____4. Ionic Bond
d. Formed when two atoms share one or more pairs
of electrons
Compounds Practice
5. What is the ratio of Carbon to Oxygen in the compound CO2?
 ______ oxygens for every ______ carbon
6. True or false. Elements usually are found on their own instead of in a compound.
7. In order to be a stable atom you must _______________________________________________.
8. True or false. Neon is likely to bond with other atoms.
Covalent Bonds Practice
Answer the following questions using the diagram of the covalent bonds in CO2 (carbon dioxide).
9. How many valence electrons does one atom of oxygen start
with? __________________
10. How many valence electrons does one atom of carbon start
with? __________________
11. How many electrons does one atom of oxygen need in order to get to a full outer shell? __________
12. How many electrons does one atom of carbon need in order to get to a full outer shell? __________
13. Why do you think carbon usually/easily bonds with TWO oxygen atoms instead of just one?
_____________________________________________________________________________________
14. How many electrons are being shared total between two oxygen and one carbon? ______________
Ionic Bonds Practice
Answer the following questions using the diagram of the ionic bond between lithium and fluorine.
15. How many valence electrons does lithium start with? ________
16. How many valence electrons does fluorine start with? _______
17. What would be easier for lithium to do in order to get a full outer
energy level?
a. bond with 7 other atoms in order to have 8 valence electrons
b. give away its 1 valence electron, and leave itself with a full 1st
energy level.
18. Originally, lithium has 3 electrons and 3 protons. The 3 negatively charged electrons cancel out the
3 positively charged protons. By giving away one electron, lithium now has ______ electrons and
______ protons. This means that lithium now has more ______________(choose one: protons OR
electrons) and becomes ________________ (choose one: positively OR negatively) charged.
19. Originally, fluorine has 9 electrons and 9 protons. The 9 negatively charged electrons cancel out the
9 positively charged protons. By accepting one electron, fluorine now has ______ electrons and
______ protons. This means that fluorine now has more ______________ (choose one: Protons OR
Electrons) and becomes _________________ (choose one: Positively OR Negatively) charged.
____20. Lithium
____21. Flourine
a. positive ion
b. negative ion
22. After electrons have been transferred, why are the ions attracted to each other to form a bond?
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