1.2 Basic ideas about atoms

Question 1

In terms of an atomic nucleus, what is radioactive decay?

Answer 1

process that takes place when an unstable atomic nucleus loses energy by radiation

Question 2

what is alpha decay?

Answer 2

A type of radioactive decay where an atomic nucleus loses two protons and two neutrons.
It is a helium nucleus
Atomic number is reduced by two and mass number by four, making the element more stable

Question 3

what is beta decay?

Answer 3

A type of radioactive decay where a beta particle is lost (an electron). And a neutron turns into a proton or vice versa.
Changes atomic number by one mass number, the same

Question 4

what is positron emission?

Answer 4

Positron emission is also known as beta decay.
Beta plus particle has the same mass, the opposite charge to an electron
When it’s released, it increases the nucleus’ proton number by one. No effect on mass number.

Question 5

What is electron capture?

Answer 5

process used by unstable, atoms to make them more stable

An electron is drawn into the nucleus and reacts with the proton to form a neutron.

Question 6

What is Alpha?

Answer 6

helium nucleus

Question 7

What is Gamma?

Answer 7

Electromagnetic wave

Question 8

What is Beta

Answer 8

fast moving electron

Question 9

What is Ionising Radiation?

Answer 9

Atoms being hit by radiation energetic enough to cause them to become ions (due to electrons being knocked off)

Question 10

Alphas ionising power

Answer 10

strongly ionising (do to being larger, it is more likely to hit something)

Question 11

Beta ionising power

Answer 11

moderately ionising

Question 12

Gamma ionising power

Answer 12

weakly ionising (due to being faster, it is less likely to hit something)

Question 13

what can alpha be blocked by

Answer 13

paper

Question 14

what can beta be blocked by

Answer 14

aluminium

Question 15

what can gamma be blocked by

Answer 15

lead

Question 16

why are some atomic nuclei unstable

Answer 16

• there is an imbalance between protons and neutrons
• they contain too much energy

Question 17

why do unstable nuclei give out radiation

Answer 17

• they undergo decay to become more stable
• as they release radiation, their stability increases

Question 18

what is the name of the process where an unstable nucleus gives out radiation to become more stable

Answer 18

radioactive decay

Question 19

alpha particle response to a magnetic field

Answer 19

Weakly attracted to the negative magnetic plate

Question 20

Beta particle response to magnetic field

Answer 20

Strongly attracted to the positive plate

Question 21

Positron response to magnetic field

Answer 21

Strongly attracted to the negative plate

Question 22

Gamma radiation response to magnetic field

Answer 22

Not affected by the magnetic field (has no change)

Question 23

define half life

Answer 23

Half-life is the time for the mass of a radioactive substance to decrease to half of its original value

Question 24

why does radioactive decay occur?

Answer 24

The radioactivity of substance decrease over time, so it can become more stable

Question 25

Give some uses of radio isotopes

Answer 25

-used in medical traces for diagnostic purposes -used medically to treat cancerous tumours -Radio dating

Question 26

Why is it bad to come in contact with certain types of radiation?

Answer 26

Radiation can damage molecules in a living cell and causes a mutation and DNA. This may make the cell become cancerous.

Question 27

Molar first ionisation energy definition

Answer 27

energy required to remove 1 mole of electrons from 1 mole of its gaseous atom to form 1 mole of 1+ ions X(g) --> X+(g) +e-

Question 28

Molar second ionisation energy definition

Answer 28

the energy needed to remove 1mole of electron in 1 mole of gaseous +1 ions to form 1 mole of gaseous ions with a +2 charge

Question 29

how does ionisation energy change attraction

Answer 29

The greater the attraction, the greater the ionisation energy

Question 30

What does attraction depend on?

Answer 30

size of nuclear charge The distance of the outer electron for the nucleus The shielding effect by electrons (in filled inner shells.)

Question 31

size of nuclear charge

Answer 31

- Greater the nuclear charge, greater the attractive force

Question 32

The distance of the outer electron for the nucleus

Answer 32

- The further the distance, the lower the attractive force

Question 33

Is ionisation energy, exothermic or endothermic

Answer 33

Endothermic

Question 34

The shielding effect by electrons (in filled inner shells.)

Answer 34

- It's the repulsion between electrons in different shells. - Electrons are all negative so repel each other. - The more filled inner shells, the lower the ionisation energy.

Question 35

On a graph of first ionisation energy, which group occupy peaks

Answer 35

group 0

Question 36

On a graph of first ionisation energy, which group occupy troughs

Answer 36

group 1

Question 37

Ionisation energy across a period

Answer 37

increases

Question 38

ionisation energy down a group

Answer 38

decreases

Question 39

what is an orbital

Answer 39

a region within an atom that can hold up to 2 atoms with opposite spin

Question 40

what is a subshell

Answer 40

a division of electron shells separated by orbitals s, p, d and f

Question 41

What rules do electrons follow when filling up orbitals

Answer 41

- electrons always enter lowest energy orbital available - electrons prefer to occupy orbitals on their own and will only pair up if there is no empty orbital of the same energy available.

Question 42

How many orbitals are there in S-subshell (and how many electrons would it hold)

Answer 42

1orbital 2 electrons

Question 43

How many orbitals are there in P-subshell (and how many electrons would it hold)

Answer 43

3 orbitals 6 electrons

Question 44

How many orbitals are there in d-subshell (and how many electrons would it hold)

Answer 44

5 orbitals 10 electrons

Question 45

How many orbitals are there in F-subshell (and how many electrons would it hold)

Answer 45

7 orbitals 14 electrons

Question 46

which electron shells, from 1-4 contain which subshells

Answer 46

1: s 2: s, p 3: s, p, d 4: s, p, d, f 4s orbital is filled before 3p

Question 47

Explain the origin of emission and absorption spectra in terms of electron transitions

Answer 47

when an electron moves down an energy level, a photon is released when an electron moves up an energy level, a photon is absorbed the wavelengths of the photons involved are seen using emission and absorption spectra

Question 48

What is the difference between absorption spectra and emission spectra

Answer 48

emission spectra =displays lines of emitted photons absorption spectra = displays spectrum with black lines for missing frequencies (of absorbed photons)

Question 49

How do you calculate ionisation energy

Answer 49

planck's constant x avogadro's constant x convergence limit

Question 50

how do you calculate frequency

Answer 50

(speed of light)/(wavelength)

Question 51

put UV, visible light, infrared radiation in order of decreasing energy

Answer 51

UV light visible light infrared radiation

Question 52

transition back to N=1

Answer 52

lymen series UV

Question 53

transition back to N=2

Answer 53

Balmer series visible light

Question 54

transition back to N=3

Answer 54

Paschen series infrared