Mass Number And Isotopes

Question 1

What are isotopes?

Answer 1

Versions of the same element with different neutron numbers are called isotopes of that element.

They have the same chemical properties.

Question 2

How many protons and neutrons does an atom of carbon-13 have?

Answer 2

An atom of carbon-13 has 6 protons and 7 neutrons.

Question 3

Answer 3

Hydrogen-2 or Deuterium

Question 4

What is mass number?

Answer 4

Mass number is the number of protons and neutrons

Question 5

Answer 5

Question 6

Answer 6

Question 7

What charge does an atom with more electrons than protons have?

Answer 7

An atom with more electrons than protons has a negative overall charge.

Question 8

What is an ion?

Answer 8

An atom with a positive or negative overall charge is called an ion

Question 9

Which of the following expressions give us the ionic charge?

Answer 9

proton number – electron number

Question 10

An oxygen atom has 8 protons and 6 electrons. What is its ionic charge?

Answer 10

2+

Question 11

The chemical symbol for oxygen is O.
What is the chemical symbol for an oxygen atom with 6 electrons?

Answer 11

Question 12

Answer 12

isotopes

Question 13

Answer 13

ion

Question 14

Answer 14

Question 15

What determines an atom’s proton number?

Answer 15

An atom’s proton number determines which element it is.

Question 16

Give the symbol for carbon, giving its proton number.

Answer 16

Question 17

Another name for proton number is

Answer 17

Atomic number

Question 18

Which of the following expressions give us the mass number?

Answer 18

proton number + neutron number

Question 19

Which of the following expressions give us the proton number?

Answer 19

mass number – neutron number

Question 20

Which of the following expressions give us the neutron number?

Answer 20

mass number – proton number

Question 21

Answer 21

Question 22

Atoms are different elements if they have a different number of ———

Atoms are different isotopes of the same element if they have the same number of ——- but different numbers of ——.

Atoms are ions if their —— and ———numbers differ.

Answer 22

Question 23

Answer 23

Question 24

Answer 24

Question 25

Answer 25

Question 26

Answer 26

35

Question 27

What is relative atomic mass?

What is an estimate of the relative isotopic mass?

Answer 27

The mass of an isotope, measured in atomic mass units or AMU, is called the relative isotopic mass.

At A-Level, it is safe to use the mass number as an estimate of the relative isotopic mass.

Question 28

An atom’s relative isotopic mass always rounds to its ——

Answer 28

mass number

Question 29

Estimate the relative isotopic mass of chlorine-37.
Give your answer to 2 significant figures.

Answer 29

37

Question 30

Answer 30

Question 31

Answer 31

neutron numbers.
mass numbers.
relative isotopic masses.

Question 32

Answer 32

51.8%

Question 33

What is the relative abundance of an isotope?

Answer 33

The relative abundance of an isotope is the number of atoms of that isotope that exists on Earth, as a percentage of all the atoms of that element.

Question 34

Answer 34

35.5 AMU

Question 35

What is relative atomic mass?
How do we calculate it?

Answer 35

The mass of an average atom of a given element is called its relative atomic mass.

We calculate it by multiplying the relative abundance of each isotope by its relative isotopic mass, and summing the products.

Question 36

Define relative atomic mass.

Answer 36

Relative atomic mass is the average mass of one atom of an element relative to one twelfth of the mass of a carbon-12 atom.

Question 37

Answer 37

58.5

Question 38

Answer 38

65.40
Zn

Question 39

Answer 39

B

Question 40

Answer 40

123

Question 41

The relative abundances of all the naturally-occurring isotopes of an element must sum to…

Answer 41

100%

Question 42

Answer 42

62.7%

Question 43

Answer 43

92.6%

Question 44

Answer 44

3.1%