Introductory Chemistry
Assessment Item 1
Question 1
Match the following terms to the most appropriate definition or description.
Term
Answer Definition/description
a) particle in the nucleus having the same mass as a proton but
with no charge
1. Compound
2. Isotopes
b) negatively charged subatomic particles having negligible
mass
c) physical state of matter where atoms are far apart with a lot
3. Mixture
of energy
d) substance of two or more elements chemically combined in
4. Atom
5. Ion
a fixed ratio
e) pure substance made of only one type of atom
f) a group of atoms
6. Atomic number
g) a charged atom or group of atoms
h) number of protons in an atom
7. Neutron
8. Mass number
i) physical state of matter with definite shape and volume
j) reaction that can be easily reversed
k) number of protons and neutrons in an atom
9. Solid
l) smallest indivisible particle of matter
m) sum of atomic weights of atoms in a molecule
10. Physical reaction
n) atoms with the same atomic number but different atomic
mass
o) something that occupies space and has mass
p) a combination that can be separated by physical means
(10 marks)
Question 2
Classify the following as a mixture, compound or element
a) table salt
b) copper
c) orange juice
d) helium
e) concrete
(5 marks)
Question 3
Identify the following as chemical or physical changes
a) filtering coffee
b) rotting eggs
c) dissolving caustic soda (sodium hydroxide) in water
d) melting solder
e) freezing meat
(5 marks)
Question 4
a) From the Periodic Table
 Give the chemical symbol for krypton
 What is its atomic number
 How many electrons and protons are there in an atom of krypton
b) Give the valencies (charge and number) of
 Magnesium
 Sulphur
 Aluminium
c) How many:
 Electrons in a bromide ion (Br-)
 Protons in a silver atom (Ag)
 Neutrons in the helium 4 isotope (4He)
(10 marks)
Question 5
Name the following compounds
a) MgCl2
b) NaNO3
c) K2O
d) SO2
e) Fe(OH)3
(10 marks)
Question 6
Give chemical formula for the following compounds
a) Sodium fluoride
b) Calcium oxide
c) Silicon dioxide
d) Copper(II) chloride
e) Potassium sulphate
(10 marks)
Total : 50 marks.