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Mid-Topic Test Revision
NAME: _______________________
form: _____________
1. Complete the following table:
Name
Democritus
How they contributed to atomic theory
Proposed that matter was made up of small, indivisible particles called atoms.
(You should have 5 main points, do some research!)
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John Dalton
Joseph J Thomson
Elements are made of extremely small particles called atoms.
Atoms of different elements differ in size, mass and other properties.
Atoms cannot be created or destroyed – matter can simply change form.
Atoms of different elements can combine to form compounds.
In chemical reactions, atoms are combined, separated or rearranged.
“Plum pudding” model of the atom: atoms consist of a large sphere that is
positively charged, with smaller, negatively charged particles embedded
throughout.
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Ernest Rutherford
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Niels Bohr
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Proposed a small, positively charged nucleus where most of the mass of
the atom is contained.
Used the gold-foil experiment to identify the nucleus in the centre of the
atom.
Postulated that the number of protons and electrons are equal.
Proposed that electrons exist in fixed orbits surrounding the nucleus.
These electron “shells” or energy levels held the electrons in orbit around
the nucleus much like a planetary system.
When excited, electrons can move between orbits.
2. Name the three sub-atomic particles that make up an atom.
Protons, neutrons and electrons
3. Describe where each of the three subatomic particles can be found within the atom.
Protons and neutrons = in the nucleus. Electrons = in shells surrounding the nucleus.
4. Define the atomic number.
The atomic number is the number of protons with the nucleus of an atom. It is unique to each element.
5. Define the mass number.
The mass number is the number of protons AND NEUTRONS in the nucleus of an atom.
6. Complete the table below:
Element
Symbol
Carbon
Aluminium
Nitrogen
Zinc
Calcium
Gold
C
Al
N
Zn
Ca
Au
Atomic
number
6
13
7
30
20
79
# protons
# electrons
6
13
7
30
20
79
6
13
7
30
20
79
Mass
number
12
27
14
65
40
197
# neutrons
6
14
7
35
20
118
7. State the maximum number of electrons that will fill in the first energy level, second energy level and third
energy level of an atom.
First = 2, second = 8 and third = 18.
8. A magnesium atom has the atomic number 12. Draw a diagram showing how the electrons would be
arranged in this atom.
1st energy level = 2 electrons
2nd energy level = 8 electrons
3rd energy level = 2 electrons
9. Draw a diagram of a Neon atom.
Neon: atomic number = 10
# protons = 10
# electrons = 10
1st shell = 2 electrons
2nd shell = 8 electrons
10. Compare the properties of metals and non-metals.
METALS: shiny, ductile, malleable, conduct electricity and heat, high melting point.
NON METALS: dull, brittle, do not conduct electricity or heat, lower melting point.
11. What do the terms “malleable”, “ductile” and “brittle” mean?
Malleable: able to be hammered or pressed into sheets or shapes without breaking.
Ductile: able to be drawn out into a thin wire.
Brittle: breaks or crumbles easily.
12. Explain why we make cooking utensils such as pots and pans out of metal rather than other materials?
Metal is a good conductor of heat and has a high melting point; therefore metal cookware allows us to
effectively heat our food without the pan melting or becoming damaged.
13. Circle the items below which are COMPOUNDS. Underline the ELEMENTS.
H
H2O
Cu
Mg
C6H12O6
14. State the difference between an atom and a molecule.
A molecule is a cluster of atoms.
Si
CO
Co