Lesson 6: Atomic Structure

Question 1

What are the subatomic particles?

Answer 1

• Protons
• Neutrons
• Electrons

Question 2

Where are protons + neutrons located?

Answer 2

• Protons + neutrons are found in the nucleus.

Question 3

Where are electrons located?

Answer 3

• Electrons are found on energy shells, orbitting nucleus.

Question 4

What is the radius of an atom?

Answer 4

1x10⁻¹⁰m

Question 5

What are the masses of protons, neutrons, electrons?

Answer 5

• Protons: 1
• Neutrons: 1
• Electrons: 1/2000 almost zero (negligible)

Question 6

Why isn’t the mass of an electron zero?

Answer 6

• Nothing has a mass of zero, that is why it is negligible.

Question 7

What are the charges of protons, neutrons, electrons?

Answer 7

• Protons +1
• Neutrons 0
• Electrons -1

Question 8

What is the atomic number?

Answer 8

• Atomic number includes number of protons.
  Number of protons = number of electrons in neutral atom.

Question 9

What is the atomic mass?

Answer 9

• Atomic mass includes number of protons + neutrons.

Question 10

How do you calculate the number of neutrons?

Answer 10

Atomic mass - Atomic number = number of neutrons

Question 11

What should you mention when given a question about atomic structure?

Answer 11

• How many protons, neutrons, electrons there are.
• Charge and mass of subatomic particles
• Where subatomic particles are located

Question 12

How many electrons fit in each shell?

Answer 12

• 2,8,8,8

Question 13

Why are the protons and electrons equal in neutral atom?

Answer 13

• Atoms are neutral.
• Protons and electrons must balance out.

Question 14

What does the period number tell you?

Answer 14

• Number of electron shells.

Question 15

What does the group number tell you?

Answer 15

• Number of electrons on outermost shell.

Question 16

Where is the mass concentrated in the atom?

Answer 16

In the atom, the mass is concentrated in the nucleus .

Question 17

What is a simple molecule?

Answer 17

• A simple molecule is a few atoms held together by covalent bonds.

Question 18

What are 2 properties of simple molecules?

Answer 18

• Low melting/ boiling points
• Do not conduct electricity, no free electrons.

Question 19

When you heat Chlroine, what forces are being broken?

Answer 19

• The intomolecular forces between the chlrorine molecules break.

Question 20

True or False. When you heat chlorine, you break the strong covalent bonds.

Answer 20

• False. When you heat chlorine, you break the intomolecular forces.

Question 21

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)

Answer 21

Group 1:
- 1 Electron on outer shell, can form H⁺ ions.
Group 7:
- Non- conductor
- Forms diatomic molecules.

Question 22

• 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)

Answer 22

• 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)

Question 23

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.

Answer 23

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

Question 24

Why is it useful to have symbols for atoms of different elements?

Answer 24

• When compound is written, tells us what atoms are involved.

Question 25

Q: Explain why a chemical reaction isn’t accurate without balancing it.

Answer 25

• The law of conservation of mass suggests atoms cannot be created or destroyed so if they aren’t the same on both sides, it isn’t accurate.

Question 26

How much smaller is the radius of the nucelus in comparison to radius of atom?

Answer 26

Less than 1/10000th of radius of atom.