Isotopes and Atomic Mass

Question 1

what is the atomic number

Answer 1

the number of protons

Question 2

what does the mass number equal?

Answer 2

protons + neutrons

Question 3

what are isotopes?

Answer 3

atoms with the same number of protons but different numbers of neutrons

Question 4

what is a mass spectrometer?

Answer 4

a thingy used to identify isotopes and their respoective abondances

Question 5

What do you need to calculate the average atomic mass?

Answer 5

• the number of isotopes
• the masses of each isotope
• the % abundance of each isotope

Question 6

what is radiation?

Answer 6

the emission of energy in the form of waves or fact moving particles. The energy carried by radiation can be transferred to matter. commond type: electromagnetiv waves

Question 7

what is ionizing radiation?

Answer 7

it consists of waves/particles that carry enough energy to remove an electron from an atom/molecule turning it into a positive ion (x-rays and microwaves, can harm tissue)

Question 8

is nuclear radiation?

Answer 8

ionizing radiation emitted from the nucleus

Question 9

Describe nuclear radiation.

Answer 9

an unstable nucleus sonpatenously emits particles and eletromagnetic radiation
- can transform one type of atom into a different one

Question 10

what is radioactivity? and what is the process called?

Answer 10

radioactivity is nuclear radiation that can trasnform one type of atom into a different one, it is called radioactive (nuclear) decay

Question 11

What is a radioactive substance?

Answer 11

a radioisotope -> one that emits nuclear radiation

Question 12

When is a nucleus unstable?

Answer 12

if it has too many or too few neutrons. If a nucleus has more than 83 protons, no number of neutrons can hold it together forever

Question 13

Usually radioactive nuclei go through a series of decays before becoming stable

Question 14

What are the three more common types of nuclear radiation?

Answer 14

• alpha particles
• beta particles
  -gamma rays

Question 15

What are alpha particles?

Answer 15

stream of fast moving helium nuclei -> a helium nucleus, which is a cluster of 2 protons and 2 neutrons

Question 16

what are beta particles?

Answer 16

stream of fast-moving electrons

Question 17

What are gamma rays?

Answer 17

high frequency electromagnetic radiation, that are often emitted along with alpha and beta radiation

Question 18

What is beta radiation?

Answer 18

a nuclear decay process that ejects a high speed electron from an unstable nucleus.

Question 19

In beta radiation how is an electron formed in the nucleus?

Answer 19

by a breakdown of a neutron into a proton an electron and an antineutrino

Question 20

When does gamma emission primarily occur?

Answer 20

after the emission of a decay particle

Question 21

Describe gamma radiation?

Answer 21

• a form a high energy electromagnetic radiation
• will not change the isotope or the element
  wavelength of the emitted gamma radiation will be unique to each isotope
• a significant health risk
• no mass
• no charge

Question 22

What are the speeds of the different kinds of decay?

Answer 22

alpha - slow
beta - fast
gamma - very fast (speed of light)

Question 23

What are the penetrating powers of the different kinds of decay?

Answer 23

alpha - low
beta - medium
gamma - high

Question 24

What can an alpha particle be stopped by?

Answer 24

paper

Question 25

what can a beta particle be stopped by?

Answer 25

aluminum

Question 26

what can a gamma ray be stopped by?

Answer 26

lead

Question 27

what is nuclear fusion?

Answer 27

two smaller nuclei come together to make a larger nuclei

Question 28

where does nuclear fusion happen naturally?

Answer 28

in centre of stars

Question 29

What produces more energy - nuclear fusion or fission?

Answer 29

fusion - it requires high heat to get reaction going

Question 30

What is nuclear fission?

Answer 30

a heavy nucleus splits into lighter nuclei

Question 31

• Nuclear fission usually needs to bombard the heavier nucleus with neutrons
• a tremendous amount of enery released
• any given nucleus ongoing fission may split into a number of different ways

Question 32

What is carbon dating?

Answer 32

using half-life to date the age of organic objects

Question 33

what does carbon-14 become during beta decay?

Answer 33

nitrogen-14.
- at time of death, organism stop absorbing carbon-14 -> since half-life in constant, the ratio of carbon-14 to nitrogen-14 provides a measurement of the age of the sample

Question 34

what is half-life?

Answer 34

the time required for half of the nuclei in a given sample of a radioactive isotope to decay. Can rage from a fraction of a second to billions of years

Question 35

what does rate of decay depend on?

Answer 35

identity of substance

Question 36

What are the differences between nuclear reactions and chemical reactions?

Answer 36

nuclear: different isotopes of an element behave differently
chemical: different isotopes of an element behave the same

nuclear: reactions are not affected by chemical state
chemical: reactions depend on chemical state

nuclear: energy changes are very large
chemical: energy changes are comparatively small