What are the subatomic particles?
- Protons
- Neutrons
- Electrons
Where are protons + neutrons located?
- Protons + neutrons are found in the nucleus.
Where are electrons located?
- Electrons are found on energy shells, orbitting nucleus.
What is the radius of an atom?
1x10⁻¹⁰m
What are the masses of protons, neutrons, electrons?
- Protons: 1
- Neutrons: 1
- Electrons: 1/2000 almost zero (negligible)
Why isn’t the mass of an electron zero?
- Nothing has a mass of zero, that is why it is negligible.
What are the charges of protons, neutrons, electrons?
- Protons +1
- Neutrons 0
- Electrons -1
What is the atomic number?
- Atomic number includes number of protons.
Number of protons = number of electrons in neutral atom.
What is the atomic mass?
- Atomic mass includes number of protons + neutrons.
How do you calculate the number of neutrons?
Atomic mass - Atomic number = number of neutrons
What should you mention when given a question about atomic structure?
- How many protons, neutrons, electrons there are.
- Charge and mass of subatomic particles
- Where subatomic particles are located
How many electrons fit in each shell?
- 2,8,8,8
Why are the protons and electrons equal in neutral atom?
- Atoms are neutral.
- Protons and electrons must balance out.
What does the period number tell you?
- Number of electron shells.
What does the group number tell you?
- Number of electrons on outermost shell.
Where is the mass concentrated in the atom?
In the atom, the mass is concentrated in the nucleus .
What is a simple molecule?
- A simple molecule is a few atoms held together by covalent bonds.
What are 2 properties of simple molecules?
- Low melting/ boiling points
- Do not conduct electricity, no free electrons.
When you heat Chlroine, what forces are being broken?
- The intomolecular forces between the chlrorine molecules break.
True or False. When you heat chlorine, you break the strong covalent bonds.
- False. When you heat chlorine, you break the intomolecular forces.
Hydrogen is an element which is difficult to fit into a suitable position in the Periodic Table. Give reasons why hydrogen could be placed in either Group 1 or Group 7. (3)
Group 1:
- 1 Electron on outer shell, can form H⁺ ions.
Group 7:
- Non- conductor
- Forms diatomic molecules.
• The three elements have similar chemical properties
• The reactivity of these elements with non-metals, increases from beryllium to magnesium to calcium.
Explain these two statements in terms of atomic structure. (6)
- Chemical reactions of metals include losing electrons.
- Have 2 electrons on outer shell/ form 2 ⁺ ions/ react in similar way. (3)
- Reactivity depends on how easily electrons are lost.
- Calcium has more electron shells so the positive charge is shielded from the negative electron.
- There is a greater distance between the positive nucleus and negative electron. Electron less drawn to it –> lost easily. (3)
Describe how sodium is similar to and how it is different from lithium in its chemical reaction with cold water.
Explain any similarity or difference in terms of their atomic structure.
Similarity: Produce alkaline solution/ hydrogen
Reason: Chemical reaction involves losing 1 electron (Na + Li both have 1 electron)
Difference: Sodium has faster reaction
Reason: outer electron easily lost
Why is it useful to have symbols for atoms of different elements?
- When compound is written, tells us what atoms are involved.
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Lesson 1 : Atoms, Elements, Compounds20
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Lesson 3: Mixtures, filtration, crystalization13
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Lesson 4: Separation by distillation20
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Lesson 5: Chromotography15
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Lesson 6: Atomic Structure26
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Lesson 7: Development of atomic model13
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History of Periodic Table13
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Allotropes of Carbon31
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Metal ores15
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States of Matter20
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Metallic Bonding/ alloys20
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Polymers13
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Conduction13
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Convection11
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Radiation12
