1c - atomic structure

Question 1

Describe the plum-pudding model

Answer 1

The atom is a ball of positive charge with negative electrons embedded in it.

Question 2

Describe the Bohr/nuclear model

Answer 2

The nuclear model suggests that electrons orbit the nucleus in energy
levels

Question 3

Later experiments led to the discovery of smaller, positive particles in the nucleus; what are these particles called?

Answer 3

Protons

Question 4

Describe the structure of an atom

Answer 4

The atom has a small central nucleus around which there are electrons.

Question 5

What did the work of James Chadwick provide evidence for?

Answer 5

The existence of neutrons in the nucleus.

Question 6

State the relative masses and relative charges of the proton, neutron and electron

Answer 6

Masses: 1, 1, very small
Charges: 1, 0 , -1

Question 7

Explain why atoms are electrically neutral.

Answer 7

They have the same number of electrons and protons

Question 8

What name is given to the number of protons in the nucleus?

Answer 8

Atomic number

Question 9

Atoms of the same element have the same number of which particle in the nucleus?

Answer 9

Protons

Question 10

Where is the majority of mass of an atom?

Answer 10

The nucleus

Question 11

What is the mass number?

Answer 11

The total number of protons and neutrons in the nucleus.

Question 12

How does one calculate the number of neutrons using mass number and atomic number?

Answer 12

Subtract the atomic number from the mass number.

Question 13

What is an isotope?

Answer 13

Atoms of the same element that have a different number of neutrons.

Question 14

What is the relative atomic
mass?

Answer 14

The average mass value of one atom, compared to 1/12 of the mass of one carbon-12 atom.

Question 15

Electrons occupy particular energy levels, with each electron in an atom at a particular energy level; which available energy level do electrons occupy?

Answer 15

The lowest available energy level

Question 16

true or false:

all atoms of the same elements have the same number of protons.

Answer 16

true

Question 17

define atomic number

Answer 17

atomic number is the number of protons in the nucleus of an atom.

Question 18

what information does the mass number give?

Answer 18

the mass number is the total number of protons and neutrons in the nucleus of an atom

Question 19

which subatomic particles are in the nucleus of an atom?

Answer 19

protons and neutrons

Question 20

what is a molecule?

Answer 20

a molecule is a group of two or more atoms held together by chemical bonds

Question 21

true or false?

atoms are made of subatomic particles

Answer 21

true.

these are protons, neutrons and electrons

Question 22

how do you determine the number of electrons in an atom?

Answer 22

number of protons/the atomic number

Question 23

state two pieces of info required to calculate the relative atomic mass

Answer 23

• the mass numbers of each isotope
• the (relative/percentage) abundances of each isotope.

Question 24

true or false?

the relative atomic mass of an element can be calculated using the atomic numbers and relative abundances of all its isotopes

Answer 24

false:

it is calculated b using the mass numbers

Question 25

in terms of isotopes, what is abundance?

Answer 25

abundance is the amount of each isotope present in a sample of an element

Question 26

how can you recognise isotopes from their chemical symbol?

Answer 26

isotopes have the same symbol and same atomic numbers but different mass numbers