Atomic Structures And Isotopes

Question 1

What is the symbol, position mass and charge of a:
Proton
Neuton
Electron

Answer 1

Proton: p+ 
Nucleus 
1
\+1
Neutron: n
Nucleus 
1
0
Electron: e-
Surrounds the nucleus 
1/2000 
-1

Question 2

What is the atomic number?

Answer 2

The number of protons

Question 3

What is the mass number?

Answer 3

The number of protons and neutrons

Question 4

What is an isotope?

Answer 4

Atoms with the same element (same number of protons) but different number of neutrons therefore have different atomic masses.

Question 5

What is an ion?

Answer 5

Charged particles formed when atoms lose or gain electrons so have different chemical properties to their atoms.

Question 6

What is a positive and negative ion?

Answer 6

Positive- atom that has lost electrons (cations)

Negative- atom that has gained electrons (anions)

Question 7

What is the relative isotopic mass?

Answer 7

Mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12

Question 8

What is the relative atoms mass (Ar)?

Answer 8

The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12

Question 9

What do you need to be able to calculate the Ar and how do you do so?

Answer 9

1. Relative isotopic mass
2. Relative abundance of each isotope

Percentage
———— X100 + (others)
100

Question 10

How can Ar be measured experimentally?

Answer 10

Mass spectrometry

Question 11

What is the Mr and how is it calculated?

Answer 11

Relative masses of compounds:

Covalent molecules: molecular mass

Formula mass: ionic compounds

Mr= sum of the Ar’s of each atom in the compound