P3- Nuclear Chemistry

Question 1

Unstable isotopes

Answer 1

Disintegrate/ decay spontaneously
As they decay, they emit particles of radiation and release energy

Question 2

Unstable nuclei/isotopes

Answer 2

They emit radiation to alter their neutrons:protons ratio to become more stable nuclei by giving out alpha, beta or gamma radiation
Radioactive and will decay

Question 3

Radioactive decay

Answer 3

Changes take place in the nucleus

Question 4

Types of radiation emitted

Answer 4

Alpha particles
Beta particles
Gamma rays

Question 5

Alpha particles

Answer 5

(a)
Consist of 2 protons and 2 neutrons
Carry a double positive charge
4
He
2
Travel only a few cm and stopped by a piece of paper
Emitted when nucleus is too large

Question 6

Beta particles

Answer 6

(B)
Electrons ejected from nucleus
Negative charge
Very low mass
0
e
-1
Travel over a metre and stopped by thin aluminium sheet
Emitted when the neutrons:protons ratio is inappropriate

Question 7

Gamma rays

Answer 7

(Y)
Electromagnetic waves emitted from weithin the nucleus of an atom
Neutral/ no charge
Travel great distance by stopped by barriers of materials like lead or concrete etc

Question 8

Proton

Answer 8

1
P
1

Question 9

Neutron

Answer 9

1
P
0

Question 10

Half life

Answer 10

The time for half of the nuclei of a particular isotope to decay

Question 11

Half life isotope

Answer 11

Constant
Unaffected by chemical/physical conditions
On,y affected by the mass of radioisotopes

Question 12

Ordinary reactions

Answer 12

Only outer electrons involved
Affected by temperature, pressure and catalysts

Question 13

Electric field deflection

Answer 13

Alpha particles deflected towards negative plate because positive charge
Beta particles deflected by a large distance (because very low mass) towards positive plate because negative charge
Gamma radiation not deflected in the electric field because no charge