atomic structure

Question 1

write an example of an ionisation equation

Answer 1

k(g)—>k+(g)+e-

Question 2

why is the outer most electron the highest energy electron

Answer 2

it is furthest from the nucleus

Question 3

why does 4s fill up before 3d

Answer 3

4s has lower energy
electrons fill up in lower energy order

Question 4

what is the atomic number

Answer 4

number of protons

Question 5

what is the atomic mass

Answer 5

number of neutrons + protons

Question 6

what is a positive ion

Answer 6

cation
has lost electrons and has more protons that electrons

Question 7

what is a negative ion

Answer 7

anion
has gained electrons and has more electrons that protons

Question 8

what is a isotope

Answer 8

atoms of the element which have the same number of protons but different number of neutrons

Question 9

what factors affect ionisation energy

Answer 9

-nuclear charge(number of protons in the nucleus)-more protons, stronger electrostatic attraction between nucleus and outermost electron so there is more energy needed to remove the outer most electron.
-shielding-electrons on a shell further away from the nucleus means there is more shielding, weaker electrostatic attraction so less energy needed to remove outermost electron.

Question 10

what does the mass spectrometer measure

Answer 10

-relative abundance
-mass/charge ratio (m/z)

Question 11

what do jumps in ionisation energy mean

Answer 11

jumps in values of consecutive ionisation energy means that the electron with a higher ionisation energy is being removed from a shell closer to the nucleus so it has a stronger electrostatic attraction and there is a big difference in its ionisation energy compared to the one before.

Question 12

what are the units of ionisation energy

Answer 12

kj/mol

Question 13

trends in first IE across a period

Answer 13

atomic radius decreases - higher proton number so higher electrostatic attraction between nucleus and outermost electron
-higher first ionisation energy

Question 14

time of flight equation

Answer 14

t=d/v
t=time (sec)
v=velocity of ion(m/s)
d= distance or length of flight tube (m)

Question 15

shape of s and p orbital

Answer 15

s= sphere
p=dumbbell shape with a cross

Question 16

results of a TOF mass spectrometer

Answer 16

if a single element is injected into a mass spectrometer it will be sperated into its isotopes
each peak is an isotope and height of the peak is the relative abundance of each isotope

Question 17

number of electrons in each shell

Answer 17

1-2
2-8
3-18
4-32

Question 18

kinetic energy equation

Answer 18

KE=1/2mv^2
kinetic energy is the energy that objects possess due to their motion
m=mass(kg)
v=velocity(m/s)
KE=kinetic energy(J)

Question 19

isotopes have the same chemical properties because..

Answer 19

they have the same electronic configuration

Question 20

how to calculate Ar

Answer 20

sum of (isotope abundance x isotope mass number)/sum of (isotope abundance)

Question 21

how many orbitals does each subshell have

Answer 21

S-1
P-3
D-5
F-7
each orbital holds 2 electrons

Question 22

exceptions of ‘normal’ electronic configuration

Answer 22

chromium and copper

Question 23

electrospray

Answer 23

sample is dissolved in volatile solvent and injected through a fine hypodermic needle to give a fine mist
tip of the needle is attatched to a positive terminal
particles gain a proton
x(g) + H+——->xH+(g)
used on higher molecular mass subtances

Question 24

electron impact

Answer 24

sample analysed is vapourised and high energy electrons are fired at it which come from an ‘electron gun’ - hot wire filament
knocks off an electron to form a 1+ ion
x(g)—>x+(g)+e-
used on substances with low formula mass

Question 25

draw and label the stages of a mass spectrometer

Answer 25

1-ionisation-2 methods but in both the sample particles get a positive charge
2-acceleration-postive ions are attracted towards the negative plate and accelerate towards it. Once accelerates all ions have the same kinetic energy
3-ion drift-ions drift towards the detector the speed they reach teh detector depends on their size
smaller ions reach faster and larger ions take longer
4-detector-each ion gains an electron then a current is generated which is proportional to the abundance of ions
5-analysis-signal from detector is passed to computer which generates a mass spectrum

Question 26

deviations in ionisation energy

Answer 26

3rd element-
The first e- removed from (element before) is from a 2s sub level
The first e- removed from(element) is from a 2p sub level
2s sub level is lower in energy than 2p so less energy needed to remove e- from (element)

6th element-
The first e- removed from(element before) is from a 2p sub level and is unpaired
The first e- removed from (element) is from a 2p sublevel and is paired
(element) has lower ionisation energy due electron paired repulsion so needs less energy to remove the electron

Question 27

describe the bohr model

Answer 27

-protons and neutrons inside the nucleus and can be called nucleons
-electrons orbit the nucleus in shells or energy levels

Question 28

describe rutherfords test

Answer 28

he fired He2+ ions at a sheet of gold foil
when the ions arrived at point p he concluded that most of the atom is empty space
some ions were deflected to point q and so he concluded that an atom must have a small positive nucleus

Question 29

definition: ionisation energy

Answer 29

the amount of energy needed to remove a mole of electrons from a mole of atoms in a gaseous state

Question 30

attraction rules to compare the size and IE’s of different elements

Answer 30

-write electronic configuration
-write number of protons
-compare shielding
if its the same compare number of protons
-compare attraction between nucleus and outer electron