Chapter 9 - Atomic And Nuclear Phenomena

Question 1

Threshold frequency

Answer 1

Min frequency of light that causes e- to be ejected

Question 2

What is the work function?

Answer 2

The minimum energy required to eject an electron

W = hFt (freq threshold)

Kmax= hf - W

Question 3

What is mass defect?

Answer 3

The diffference between actual nucleus mass and the sum of the masses of all protons and neutrons within it

Question 4

Fusion

Answer 4

Small nuclei combine to form a larger nucleus

Question 5

Fission

Answer 5

Large split into small

Question 6

Alpha decay

Answer 6

Émission of an alpha particle

He nucleus consisting of two protons, two neutrons and zero electrons

Mass will be 4 less
Atomic number will be two less

Question 7

Bêta decay

Answer 7

Émission of beta particle

• neutron turns into a proton and makes a new electron
• mass doesn’t change …but the element changes (# protons has changed!)

ß- decay or e-

Question 8

Positron emission

Answer 8

Form of beta decay but positron released

e+ or ß+

**a neutrino is also emitted (omitted on mcat)

Mass doesn’t change, atomic number is one lower

Question 9

GAMMA DECAY

Answer 9

Émission of gamma rays

• high frequency photons
• nothing changes (mass or atomic number)

***this is easy to answer!

Question 10

Electron capture

Answer 10

Reverse B- decay

X + e- -> (one less proton)

Question 11

Half life

Answer 11

Do some problems

Question 12

Exponential decay equation

Answer 12

9.12