Atomic structure and the periodic tabe

Question 1

Relative mass of proton

Answer 1

1

Question 2

Relative mass of neutron

Answer 2

1

Question 3

Relative mass of electron

Answer 3

1/1840 (negligible)

Question 4

Nucleon number

Answer 4

The total number of protons and neutrons in the nucleus of an atom

Question 5

Isotopes

Answer 5

Atoms of the same element which have the same proton number but a different nucleon number

Question 6

Why do isotopes have the same chemical properties?

Answer 6

Because they have the same number of electrons in their outer shell

Question 7

One industrial use of radioactive isotopes

Answer 7

Uranium - 235 is used as a controlled source of nuclear energy in nuclear power stations

Question 8

Medical use of radioactive isotopes

Answer 8

Cobalt - 60 is used to treat internal cancer tumours using gamma radiation

Question 9

Difference between relative atomic mass and mass (isotopic) number

Answer 9

Relative atomic mass (Ar) is the average of the mass numbers of different isotopes of that element. Mass number is the total number of protons and neutrons in the nucleus of an atom of that element

Question 10

What is relative atomic mass (Ar) ?

Answer 10

The average mass of naturally occuring atoms of an element on a scale where the Carbon-12 atom has a mass of exacly 12 units

Question 11

Relative molecular mass/ relative formula mass (Mr)

Answer 11

The sum of the relative atomic masses