Atomic Structure

Question 1

Define atomic number

Answer 1

The total number of protons in an atom

Question 2

Define mass number

Answer 2

The total number of protons and neutrons in an atom

Question 3

Define element

Answer 3

A substance that consists of a single type of atom which cannot be split into anything simpler by chemical means

Question 4

Define compound

Answer 4

Is two or more different elements chemically combined

Question 5

Ions
Cations
Anions

Answer 5

Atoms with electric charges
Atoms with positive charge
Atoms with negative charge

Question 6

Isotopes

Answer 6

Atoms of an element with the same atomic number but a different mass number indicating a different number of neutrons

Question 7

Draw an atom

Answer 7

• nucleus
• orbiting electrons
• protons
• neutrons

Question 8

What was the Plum Pudding model? (2)

Answer 8

• The 1897 ‘Plum Pudding’ model of J.J Thomson

- stated that the negative electrons were embedded in a positive sphere (like the raisins in a plum pudding).

Question 9

Who discovered the electron?

Answer 9

J J Thomson

Question 10

Who discovered the nucleus?

Answer 10

Ernest Rutherford

Question 11

What part of the atom did James Chadwick discover in 1932 ?

Answer 11

Neutrons

Question 12

Who discovered the proton?

Answer 12

Ernest Rutherford

Question 13

In 1808 John Dalton published his Atomic Theory. What did he state?

Answer 13

Dalton stated “all elements are made up of small invisible particles called atoms”

Question 14

Give the relative mass, relative charge and position of a proton, neutrons and electron

Answer 14

Proton - relative mass: 1
Relative charge: +1
Position: nucleus

Neutron - relative mass
Relative charge: 0
Position: nucleus

Electron - relative mass 1/1840
Relative charge: -1
Position: shell

Question 15

Calculate the relative atomic mass of chlorine

Answer 15

Average mass number = (75x35)+(25x37)
100
= 35.5

Question 16

Who discovered the neutron?

Answer 16

James Chadwick

Question 17

Who do atoms have no charge ?

Answer 17

Number of electrons equals the no. of protons and they cancel each other out

Question 18

What did Ernest Rutherford revise J.J Thompson’s model to ?

Answer 18

To the model which has electrons orbiting a positive nucleus

Question 19

What is today’s model of the atom ? (2)

Answer 19

• Central nucleus - containing positive protons and neutral charge neutrons which make up most of the mass
• Orbiting around the nucleus in shells are negatively charged electrons

Question 20

How to work out number of neutrons

Answer 20

Mass number - Atomic number
(protons + neutrons) - (protons=electrons)
so neutrons = protons - electrons

Question 21

Radius of an atom and nucleus

Answer 21

0.1nm

The nucleus is less than 1/10000 of that of the atom

Question 22

Isotope Definition

Answer 22

Isotopes are atoms of an element with the same atomic number but a different mass number indicating a different number of neutrons