Download Quiz #3 Review

Compounds Review
Review Questions
1. What is the difference between the atomic number and the atomic mass of an element?
Atomic number is determined by how many protons are in an atom; it
indicates the placement of that atom on the Periodic Table. The atomic
mass of an element is made up by the mass of protons and neutrons
within that atom; the atomic mass is usually more that the atomic
number.
2. If tin’s mass number is 119 and its atomic number is 50, how many neutrons are in the
nucleus of an atom of tin?
119-50 = 69 neutrons
3. Correct the following statements about the periodic table.
a. Neon has 11 protons Neon has 10 protons
b. The symbol for sodium is So The symbol for sodium is Na.
c. Beryllium has 4 neutrons Beryllium has 5 neutrons.
d. Boron and aluminum are metals (any other metal) and aluminum are metals.
e. Chlorine has 16 electrons Chlorine has 17 electrons.
4. Match the elements in the list below with one of the following two descriptions
i. Shiny, ductile, conductor of electricity OR
ii. Dull, brittle insulator
a. P (ii)
d. F (ii)
b. W (i)
e. Hg (i)
c. Cu(i)
f. K (i)
5. Match the term on the left with the description on the right
a. Alkali metal (iii)
i. A combination of two or more elements
b. Halogen (v)
ii. An unreactive non-metal
c. Element (iv)
iii. Very reactive metal
d. Compound (i)
iv. A pure substance of the same atoms
e. Noble gas (ii)
v. Very reactive non-metal
6. Three containers each hold a different “mystery” element. Four of their properties are
shown below. Identify which element is (a) a non-metal, (b) an alkali metal, and (c) a
noble gas
Colour
State at room
Reactivity
Conductivity
temperature
Element X
Green-yellow
Gas
High
No
(non-metal)
Element Y
Colourless
Gas
None
No
(noble gas)
Element Z
Silver-grey
Solid
High
yes
(metal)
7. What information can you determine from a chemical formula?
You can determine the elements that make up the compound and how many of each
there are.
8. Identify the state and the elements in each of the following compounds
a. HF(g) This is a gas made up of one Hydrogen and one Flourine atoms.
b. Li2O(s) This is a solid made up of two Lithium and one Oxygen atoms.
c. K3P(s) This is a solid made up of three Potassium and one Phosphorous atoms.
d. Ni2O3(s) This is a solid made up of two Nickel and three Oxygen atoms.
e. HgCl2(s) This is a solid made up of one Mercury and two Chlorine atoms.
9. How many atoms are indicated in the formula of each of the following compounds?
a. AgCl(s) One silver, One Chlorine
b. CaO (s) One Calcium, One Oxygen
c. Mg3N2(s) Two Magnesium, Two Nitrogen
d. Al2O3(s) Two Aluminum, Three Oxygen
e. Sc2S3(s) Two Scandium, Three Sulphur
10. Write the chemical formula for each of the following compounds:
a. Sodium sulfide, which has two atoms of sodium and one atom of sulfur Na2S
b. Aluminum fluoride, which has one atom of aluminum and three atoms of
fluorine AlF3
c. Oxygen gas, which has two atoms of oxygen O2
d. Glucose which has six carbon atoms, 12 hydrogen atoms, and six oxygen atoms
C6H12O6
11. What is an ionic compound? A metal and a non-metal bonded by shared electrons and
electric charge
12. List three properties of all ionic compounds.
All ionic compounds
- have high melting points (and are solid at room temperature)
- Make good conductors when dissolved in water
- Form crystals
13. Define a molecular compound and give an example of one.
A molecular compound is formed when two or more non-metals are joined
together by sharing the electrons in their valence (or outer) shell. Another name
for molecular bond is a Covalent bond (because they share valence electrons).
There are many molecular compounds, the most common are water (H2O), Carbon
Dioxide (CO2) and Oxygen (O2).
14. List three properties of a molecular compound.
Molecular compounds
- May be solid, liquid or gas at room temperature
- Tend to be insulators or poor conductors
- Have low melting and boiling points
15. Which of the following compounds are molecular?
a. H2O Molecular
b. NaCl Ionic
c. NH3 Molecular
d. F2 Molecular
e. CuCl2 Ionic
f. CCl4 Molecular
16. Complete questions from Saskatchewan Science 9 on page 194 #1, 5, 6-9, 11, 15a.
Page 194
1. The smallest amount of a pure substance is called an atom.
5. Any four of Boron, Silicon, Carbon, Phosphorus, Sulphur, Germanium, Arsenic,
Selenium, Antimony, Tellurium, Iodine, Poloniium, Astatine would be correct.
6. A compound is a pure substance made up of two or more elements which have
been chemically combined.
7. (a) Mercury was classified as a metal because it is a shiny silvery material that is a
good conductor. (b) Mercury is different from most metals because it is a liquid.
8. a) Technetium (Tc) has 43 protons in one atom of its elemental form.
b) Dysprosium (Dy) has 66 electrons in its elemental (non-ionized) form.
9. a) 2 atoms of Hydrogen and 2 atoms of Oxygen.
b) H2O2 is a molecular or covalent compound because it is two non-metals held
together by sharing their outer electron shell (valence shell).
c) Hydrogen Peroxide is used to kill bacteria on hair or on skin and is also used as a
bleaching agent.
11.
15. a) Carbon also occurs in pure form as graphite and coal.