LO 85 - 86

Question 1

Given the isotope ^A _Z X what does each letter represent?

Answer 1

A represents the mass number (proton + neutrons) of element X while Z represents the atomic number (protons)

Question 2

¹ ₁ p

Answer 2

proton

Question 3

¹ ₀ n

Answer 3

neutron

Question 4

⁰ _-1 e

Answer 4

electron

Question 5

______________ decay occurs when an unstable nucleus emits a particle composed of two protons and two neutrons

Answer 5

Alpha (α)

Question 6

α particle = ________

Answer 6

⁴ ₂ He

Question 7

In alpha decay the mass number ________________ and the atomic number ____________________

Answer 7

decreases by 4
decreases by 2

Question 8

Alpha particles have the highest _______________________ which can damage other molecules due to their size and activity

Answer 8

ionizing power

Question 9

Alpha particles have the lowest ____________________ into matter and can be stopped by paper or clothing

Answer 9

penetrating power

Question 10

_______________ decay occurs when an unstable nucleus emits an electron

Answer 10

Beta (β)

Question 11

β particle = _____________

Answer 11

⁰ _-1 e

Question 12

What happens to the neutron in beta decay?

Answer 12

¹ ₀ n → ¹ ₁ p + ⁰ _-1 e

Question 13

In beta decay the mass number is _____________ while the atomic number __________________________

Answer 13

unchanged
increases by 1

Question 14

beta decay is ___________ damaging than alpha decay but has a higher ____________

Answer 14

less
penetrating power

Question 15

__________________ are a form of electromagnetic radiation that are high-energy, short-wavelength photons

Answer 15

Gamma (γ) rays

Question 16

gamma ray =_______

Answer 16

⁰ ₀ γ

Question 17

gamma rays are usually from ________ or in conjunction with processes such as _________________________

Answer 17

excited atoms
alpha / beta decay

Question 18

After alpha or beta decay some atoms enter a ________ state before they release _____________

Answer 18

metastable
gamma rays

Question 19

Gamma rays have the lowest __________________ but the highest __________________ that could need thick concrete to stop

Answer 19

ionizing power
penetrating power

Question 20

_________________ occurs when an unstable nucleus emits a ______________, the antiparticle of an electron which collides with an e-, annihilate each other, and produce ____________

Answer 20

positron emission
positron
gamma rays

Question 21

positron = ____________

Answer 21

⁰ ₊₁ e

Question 22

What happens to the proton in positron emission?

Answer 22

¹ ₁ p → ⁰ ₊₁ e + ¹ ₀ n

Question 23

In positron emission the mass number is ___________ while the atomic number _____________________

Answer 23

unchanged
decreases by 1

Question 24

______________ involves a particle being absorbed not emitted and occurs when the nucleus assimilates an e- from an inner orbital

Answer 24

electron capture

Question 25

What happens to the proton in electron capture?

Answer 25

¹ ₁ p +⁰ _-1 e → ¹ ₀ n

Question 26

In electron capture the mass number is ___________ while the atomic number _____________________

Answer 26

unchanged
decreases by 1

Question 27

A nucleus is composed of ______________ which consists of the protons and neutrons. Since the positive force of the protons wants to repel the ___________ holds the nucleus together

Answer 27

nucleons
strong force

Question 28

A high (>1) neutron/Atomic Number ratio (N/Z) tends to result in . . .

Answer 28

beta decay

Question 29

A low (<1) neutron/Atomic Number ratio (N/Z) tends to result in . . .

Answer 29

positron emission or e- capture

Question 30

A large number of the stable nuclei have an ________ number of protons and neutrons

Answer 30

even

Question 31

Atoms with Z > ___ are radioactive and decay in one or more steps via alpha or beta decay

Answer 31

83

Question 32

What are the magic numbers for unique nucleus stability?

Answer 32

N or Z = 2,8,20,28,50,82
N = 126