atomic structure

Question 1

what is A

Answer 1

mass number

Question 2

what is Z

Answer 2

proton number

Question 3

protons, neutrons and electrons relative charge and relative mass

Answer 3

charge :
P+1
E-1
N 0
mass;
P 1
E1/1840
N1

Question 4

an atom consists of

Answer 4

nucleus containing protons and neutrons surrounded by electrons

Question 5

what is an isotope

Answer 5

are atoms with the same number of protons but a different number of neutrons

Question 6

what is ionisation energies

Answer 6

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

Question 7

maximum number of electrons in each shell

Answer 7

1- two
2- eight
3-eighteen
4-32

Question 8

how many orbitals in each subshell

Answer 8

s- one
p-three
d-five

Question 9

execpetions in d orbital

Answer 9

chromium- one elctron from 4s subshell moved up to 3d subshell so half ful so more stable
copper- one elctron from 4s subshell moved up to 3d subshell so ful so more stable
d-block ions - electrons are lost from 4s orbtital first

Question 10

steps of time of flight mass spectorometre

Answer 10

1- vacuum, the entire machine is a vacuum inside to prevent any of the particles being tested colliding with molecules from the air
2- ionisation, electron impact or electrospray ionization to form positive ion
3- acceleration , the positive ions attracted to a negatively charged plate, all have same kinetic energy, the amount they accerlareate depends on the mass to charge ratio of the ion, lower mass charge ratio go faster
4- ion drift, some of the ions pass through hole in negatively charged plate, travel along flight tube towards detector, as particles now travelling at different speedsthey drift further apart
5- detection, differnet m/z ratio ions arrive at differnet times the time of flight is recorded, as each ion hits detector it gains an electron which generates a current which is proportional to the abundance of each type of ion
6- data anylasis, signal from detector sent to a computer which genertaes mass specturum

Question 11

what is electron impact ionistions

Answer 11

sample vaporized
high energy electrons are fired at it from an electron gun
knocks off one electron from each particle forming a 1+ ion

Question 12

what is electrospray ionisation

Answer 12

sample is dissolved in volatile solvent and injected through a fine hypodermic needle to give a fine mist, the needle tip attached to the positive terminal of a high voltage power supply, particles gain a proton

Question 13

what is mass spectrometry used for

Answer 13

to identify elements and determine relative molecular mass

Question 14

kinetic energy eqaution

Answer 14

1/2mv^2

Question 15

calcutlating ar

Answer 15

(mass 1 x abundance 1)+(mass 2 x abundance 2)+…/ sum of abundances