2. Atomic Structure

Question 1

Define an Element.

Answer 1

A substance made of atoms that all contain the same number of protons and cannot be split into anything simpler.

Question 2

Define a Compound.

Answer 2

A pure substance made up of two or more elements chemically combined.

Question 3

Define a Mixture.

Answer 3

A combination of two or more substances that are not chemically combined (can be separated by physical means).

Question 4

What are the three subatomic particles?

Answer 4

Protons, Neutrons, Electrons.

Question 5

What is the relative mass and charge of a Proton?

Answer 5

Mass: 1, Charge: +1.

Question 6

What is the relative mass and charge of a Neutron?

Answer 6

Mass: 1, Charge: 0.

Question 7

What is the relative mass and charge of an Electron?

Answer 7

Mass: 1/1840 (negligible), Charge: -1.

Question 8

Define Atomic Number (Z).

Answer 8

The number of protons in the nucleus of an atom.

Question 9

Define Mass Number (A) (Nucleon Number).

Answer 9

The total number of protons and neutrons in the nucleus.

Question 10

How do you calculate the number of Neutrons?

Answer 10

Mass Number - Atomic Number.

Question 11

Why is an atom electrically neutral?

Answer 11

Because the number of positive protons equals the number of negative electrons.

Question 12

Define Isotopes.

Answer 12

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 13

Do isotopes have different chemical properties?

Answer 13

No, because they have the same electronic structure (same number of outer electrons).

Question 14

How do you calculate Relative Atomic Mass (Ar) from isotopes?

Answer 14

((% of Isotope A × Mass A) + (% of Isotope B × Mass B)) / 100.

Question 15

What is the maximum number of electrons in the first three shells?

Answer 15

2, 8, 8.

Question 16

What does the Group number tell you?

Answer 16

The number of electrons in the outer shell.

Question 17

What does the Period number tell you?

Answer 17

The number of electron shells the atom has.

Question 18

Where are Metals located on the Periodic Table?

Answer 18

On the left side.

Question 19

Where are Non-Metals located on the Periodic Table?

Answer 19

On the right side (separated by the zigzag ‘staircase’).

Question 20

Compare the conductivity of Metals and Non-Metals.

Answer 20

Metals conduct heat and electricity; Non-metals (usually) do not.

Question 21

What type of oxides do Metals form?

Answer 21

Basic oxides.

Question 22

What type of oxides do Non-Metals form?

Answer 22

Acidic or Neutral oxides.

Question 23

Why do Group 0 (Noble Gases) not react?

Answer 23

They have a full outer shell of electrons, making them stable.

Question 24

A sample of Rubidium is 72% Rb-85 and 28% Rb-87. Calculate the Relative Atomic Mass.

Answer 24

(72 * 85) + (28 * 87) / 100 = 85.6

Question 25

Chlorine has an atomic number of 17. Is it 2,8,7 or 2,8,8,1?

Answer 25

2, 8, 7. (2 in first, 8 in second, remaining 7 in third).

Question 25

An ion has a charge of 2+. It has 12 protons and 12 neutrons. How many electrons does it have?

Answer 25

10 electrons. (It lost 2 electrons to become positive).

Question 26

Is Air a compound or a mixture?

Answer 26

Mixture. It contains chemically uncombined gases (Nitrogen, Oxygen, Argon, CO2).