Atomic Structure and Atomic Mass

Question 1

What is an atom?

Question 2

What are atoms made up of

Answer 2

All atoms are made up of a small, positively charged nucleus surrounded by a much larger cloud of negatively charged electrons, as shown

The nucleus is made up of two types of subatomic particles—protons and neutrons.

Question 3

What is electrostatic attraction?

Answer 3

Is when negative particles attract positive particles.

Question 4

What is the atomic number?

Answer 4

The number of protons in an atom’s nucleus is known as the atomic number and is represented
by the symbol Z.

All atoms that belong to the same element have the same number of protons and therefore have the same atomic number

Question 5

What is the Atomic Mass?

Answer 5

• The number of protons and neutrons in the nucleus of an atom is known as the mass number
• Represented by the symbol A. The mass number
• Represents the total mass of the nucleus.

Question 6

What are isotopes?

Answer 6

Same element different numbers of neutrons (and therefore different mass numbers)are known as isotopes.

Isotopes have identical chemical properties but different
physical properties, for example different masses and densities.

Question 7

What determines the type of atom that makes up each element?

Answer 7

The number of protons in the nucleus

Question 8

What is the atomic number represented by?

Answer 8

The symbol Z

Question 9

What do all atoms of the same element have in common?

Answer 9

The same number of protons and the same atomic number, Z

Question 10

What is the mass number represented by?

Answer 10

The symbol A

Question 11

What does the mass number represent?

Answer 11

The total mass of the nucleus

Question 12

What is the relationship between protons and electrons in a neutral element?

Answer 12

The number of protons is equal to the number of electrons

Question 13

For carbon atoms, what is the atomic number Z?

Answer 13

6

Question 14

How is the standard representation of an atom shown?

Answer 14

With its atomic number and mass number

Question 15

What is the number of protons in an aluminium atom?

Answer 15

13

Question 16

How do you calculate the number of neutrons in an atom?

Answer 16

Mass number (A) - Atomic number (Z)

Question 17

If the atomic number is 18, how many protons does the atom have?

Answer 17

18

Question 18

If the mass number is 40 and the atomic number is 18, how many neutrons are there?

Answer 18

22

Question 19

What is the definition of isotopes?

Answer 19

Atoms that have the same number of protons but different numbers of neutrons

Question 20

What do isotopes have in common?

Answer 20

Identical chemical properties with different physical properties

Question 21

What differs among isotopes of the same element?

Answer 21

Their physical properties, such as different masses and densities

Question 22

What are the mass numbers for hydrogen isotopes?

Answer 22

• 1 (protium) * 2 (deuterium) * 3 (tritium)

Question 23

Fill in the blank: The number of protons and neutrons in the nucleus is known as the _______.

Answer 23

mass number

Question 24

True or False: All hydrogen atoms have the same mass number.

Answer 24

False

Question 25

What are the three carbon isotopes?

Answer 25

Carbon-12, Carbon-13, Carbon-14

Question 26

What are radioisotopes?

Answer 26

Isotopes that are radioactive

Question 27

What is the band of stability?

Answer 27

A region where nuclei are stable

Question 28

What happens to nuclei that lie outside the band of stability?

Answer 28

They are unstable and radioactive

Question 29

What do radioisotopes do during decay?

Answer 29

They emit radiation in the form of alpha particles, beta particles, or gamma radiation

Question 30

What are alpha particles composed of?

Answer 30

Two protons and two neutrons

Question 31

How far can alpha particles travel from their source?

Answer 31

No further than a few centimetres

Question 32

What can stop alpha particles?

Answer 32

A sheet of paper or equivalent material

Question 33

What are beta particles?

Answer 33

High-energy electrons formed from the decay of nuclei with too many neutrons

Question 34

What can block beta particles?

Answer 34

An aluminium plate several centimetres thick

Question 35

What happens during the production of a beta particle?

Answer 35

A neutron is converted to a proton, increasing the atomic number by one

Question 36

What is gamma radiation?

Answer 36

A type of high-energy electromagnetic radiation

Question 37

What can stop gamma radiation?

Answer 37

Something as dense as a lead plate several centimetres thick

Question 38

How can the decay of radioisotopes be represented?

Answer 38

By equations of balanced nuclear reactions

Question 39

What does the Greek letter y represent in nuclear equations?

Answer 39

Gamma radiation

Question 40

What must be checked when writing an equation for a balanced nuclear reaction?

Answer 40

The atomic numbers and mass numbers must add up to the same value on both sides

Question 41

What does carbon-14 decay produce?

Answer 41

Beta particles (electrons)

Question 42

What is carbon dating?

Answer 42

A technique used to determine the age of a once-living organism

Question 43

How does the ratio of carbon-12 to carbon-14 change after an organism dies?

Answer 43

It decreases as the carbon-14 decays