1.2 basic ideas about atoms

Question 1

proton

Answer 1

Proton = atomic number

Question 2

neutron

Answer 2

Neutrons = mass number - atomic

Question 3

electron

Answer 3

Electrons = number of protons

Question 4

define isotope

Answer 4

Atoms that have the same number of protons but different number of neutrons

Question 5

what is Radioactive decay

Answer 5

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

Question 6

Alpha decay

Answer 6

Cluster of 2 protons and 2 neutrons, positively charged.

It reduces the atomic number by 2 and mass number by 4.

PRODUCT IS TWO PLACES TO THE LEFT

Question 7

Beta decay

Answer 7

A fast moving electron and a neutron turn into a proton or a proton turns into a neutron.

Atomic number increases by 1 and the mass number is unchanged. Negatively charged.

PRODUCT IS ONE PLACE TO THE RIGHT IN PT

Question 8

Position emission

Answer 8

Another type of beta decay (beta +)

Proton converted to a neutron whilst releasing a positron and an electron neutrino.

Decreases proton number by 1 but has no effect on mass number

product is one place to the left in the periodic table

Question 9

Electron capture

Answer 9

Process to make unstable atoms stable.

Product is ONE PLACE TO THE LEFT

MASS NUMBER UNCHANGED, ATOMIC NUMBER DECREASES BY 1

Question 10

what are alpha, beta and gamma blocked by?

Answer 10

alpha - least penetrating - absorbed by a few cm of air or a sheet of paper

beta - absorbed by a few mm of aluminium

gamma - most penetrating - absorbed by a few cm of lead or 1m of concrete

Question 11

How are alpha beta and gamma affected by electric fields

Answer 11

Alpha particles are positively charged + Beta particles are negatively charged so they are both deflected by electric field (alpha to neg plate beta to pos plate)

Gamma stays the same since it’s neutral.

Question 12

Ionising powers of alpha beta and gamma

Answer 12

Alpha - very strong ionising power

Beta - medium ionising power

Gamma - weak ionising power

Question 13

Compare the penetrating power of alpha, beta, and gamma radiation

Answer 13

alpha
beta
gamma

Question 14

Gamma

Answer 14

high energy electromagnetic radiation

Question 15

Radioactivity half life

Answer 15

Time it takes for half the atoms in a radioisotope to decay.

Question 16

How does radiation affect living cells

Answer 16

Damages cells and changes the way the cell functions,

Can cause a mutation in DNA which can become cancerous at lower doses and at higher doses the cell can die.

Gamma rays are more dangerous outside body and alpha rays are more dangerous inside body

Question 17

Radioactivity in medicine

Answer 17

cobalt 60
technetium 99

Question 18

what is cobalt 60 used for

Answer 18

cobalt 60 is used as a treatment for cancer in radiotherapy

Question 19

what is technetium 99 used for

Answer 19

-technetium 99m used as a medial radioisotope as a tracer

Question 20

Radioactivity in radiodating

Answer 20

carbon 14
potassium 40

Question 21

what is cobalt 14 used for

Answer 21

Caron 14 used to call age of plants and animals as it has a large half life.

Question 22

what is potassium 40 used for

Answer 22

Potassium 40 to estimate age of rocks.

Question 23

Radioactivity in industry and analysis

Answer 23

ANALYSIS AND INDUSTRY:

Thickness monitoring of metal strips or foil

Dilution analysis to find mass of a substance in a mixture

Question 24

how many electrons does s,p,d,f orbitals hold

Answer 24

s shell: spherical, can hold 2 electrons per energy level

p shell: can hold 6 electrons per energy level

3 p orbitals

d shell: long balloons connected at the center, can hold 10 electrons per energy level

f shell: similar to d-shell, only more complicated, can hold 14 electrons

Question 25

define first ionisation energy

Answer 25

The molar first ionisation energy of an element is the energy required to completely remove 1 mole of electrons from 1 mole of its gaseous atoms to form 1 mole of gaseous ions. X(g) —— X+ (g) + e-

Question 26

Ionisation energy is exothermic or endothermic

Answer 26

endothermic

Question 27

Factors affecting ionisation energy

Answer 27

Nucleus charge - greater the nucleus charge the greater the attraction for the outer electron Electron shielding - filled inner shells or sub shells of electrons act as shields so the outer electron is shielded from nucleus charge by these shells. Distance from outer shell from nucleus - attraction decreases the further away the outer electron is from nucleus

Question 28

Trends in ionisation energies

Answer 28

increases across a period decreases down a group

Question 29

why does ionisation energies increase across a period

Answer 29

increases across a period because number of protons increase and electron shielding remains similar so across a period the require more energy to overcome nucleus attraction.

Question 30

why does ionisation energies decrease down a group

Answer 30

decreases down a group because atomic radius and electron shielding increases so nucleus attraction with the electron gets weaker making the electron easier to remove.

Question 31

How do successive ionisation energies tell you which group an element belongs to

Answer 31

a large increase between 2 different successive ionisation energies for example 7 and 8th ionisation energies suggests the 8th electron is being taken away from a new full stable shell. Therefore there are 7 electrons in its outer shell so belongs to group 7.

Question 32

Why are 4s orbitals filled before 3d orbitals?

Answer 32

4s are at lower energy so they are filled first

Question 33

What 2 elements are exception to the rule that 4s orbital is filled first

Answer 33

Chromium and copper

Question 34

Why does beryllium have higher ionisation energy than boron ?

Answer 34

Beryllium has a stable, fully-filled 2s orbital (2s²), making it harder to ionize compared to boron, which has an electron in the higher-energy 2p orbital (2p¹), which is easier to remove.

Question 35

What determines the chemical properties of an element

Answer 35

Electron configuration

Question 36

Shapes of p and s orbital

Answer 36

S - spherical P- dumbbell shaped

Question 37

Absorption spectrum

Answer 37

White light is passed through a vapour of a particular element some wavelengths will be absorbed by the atoms of the elements and removed from the white light.

Question 38

What's the difference between absorption and emission spectra

Answer 38

Emission spectra displays lines at frequents of emitted photos with coloured lines and a black background Absorption displays the entire spectrum with black lines for the missing frequencies of the absorbed photons.

Question 39

Equation for energy and frequency

Answer 39

E = h x frequency

Question 40

Equation that links frequency and wavelength

Answer 40

F = speed of light/wavelength

Question 41

Order of increasing energy of visible light, ultraviolet light and infrared

Answer 41

Infrared - visible light - uv light

Question 42

Lyman series (ultraviolet)

Answer 42

A set of spectral lines that appear in the UV region when a hydrogen atom undergoes a transition from energy levels n>1 to n=1.

Question 43

Balmer series (visible )

Answer 43

A set of spectral lines that appear in the visible light region when a hydrogen atom undergoes a transition from energy levels n>2 to n=2.

Question 44

Paschen series (infrared)

Answer 44

the series of lines in the spectrum of the hydrogen atom which corresponds to transitions between the state with principal quantum number n = 3 and successive higher states

Question 46

Why does nitrogen (N) have a higher ionization energy than oxygen (O)?

Answer 46

Nitrogen has a stable half-filled 2p orbital (2p³), which minimizes electron-electron repulsion, while oxygen has an extra electron in the 2p orbital (2p⁴), increasing repulsion and making it easier to ionise.