Atomic Structure and Amount of substance

Question 1

Atomic number definition

Answer 1

The total number if protons in an atom of an element

Question 2

Definition mass number

Answer 2

The total number of protons and neutrons in an atom of an element

Question 3

What charge are cations

Answer 3

Positive

Question 4

What charge are anions

Answer 4

Negative

Question 5

relative atomic mass definition ;

Answer 5

an average mass of an element in comparison to an atom of carbon 12 mass

Question 6

what is definition of relative molecular mass ;

Answer 6

average mass of 1 formula of that compound compared to 1 atom of carbon

Question 7

relative isotopic mass definition ?

Answer 7

mass of an isotopic mass in comparison with 1 / 12 of the mass of an carbon 12 atom

Question 8

proton , neutron and electron charges

Answer 8

+1 , 0 , -1

Question 9

proton neutron and electron masses

Answer 9

1, 1, 1/1840

Question 10

define an isotope

Answer 10

atoms of the same element with the same number of proton and electrons but different number of neutrons

Question 11

define an ion

Answer 11

element with the same number of protons and neutrons but different number of electrons

Question 12

RAM equation :

Answer 12

( isotope 1 mass no x % abund of iso1 ) + ( isotope 2 mass no x isotope abunance % of iso 2 ) divided by 100

Question 13

order of development of the atom :

Answer 13

Democitrius - atoms can not be broken down into smaller particles
Aristotole - discovered 4 elements matter is made of : fire , air , earth , water
Boyle - modern version of elements
Dalton - atoms are spheric balls - cannot be created or destroyed , atoms of same element are the same and atoms of different atoms are different + created some chemical symbols
Faraday & Davey - by electrolysis discovered matter is electrical in nature
Crookes - cathod ray discovery by cathod ray tube ( eventually called electrons )
Thompson - plum pudding model +ve charge with negative electrons embedded in it
Goldstein - behind cathode rays are +ve rays emitted . type of ray depemnds on gas in tube . eventually called proton by rutherford .
Bequeral - radioactivity
Geiger and Marsden ( rutherfords students ) gold leaf experiment
Chadwick - neutrons
Bohr - protons

Question 14

geiger & marsden
rutherford students discovery

Answer 14

most alpha particle went straight through - atoms have ;ots of empty space
some alpha particles were deflected - particles must have passed something ( nucleus )
some alpha particles were deflected right back to where they came from - hit something dense and positivly charged ( nucleus )

Question 15

how to find percentage abundance of an isotope using ToF

Answer 15

the size of the current produced when the ion hits the detector allows us to discover the abundance of the isotope .

Question 16

how to find mass of an isotope

Answer 16

time taken for an ion to drift down the chamber

Question 17

how do elements with low formula mass become ionised :

Answer 17

electron impact -
the sample is vaporised
high energy e- are fired at it . They ‘knock; an electron off leaving the sample to form positive ions .
they are attracted towards a negative electron plate .

Question 18

how do elements with a high formula mass become ionised :

Answer 18

electrospray ionisation
sample is dissolved in a volatile solvent
injected through hypodermic needle
particles become ionised by gaining protons from a solvent
produce xh ions
attract to negative plate .

Question 19

what happens at ToF:

Answer 19

sample placed in a chamber
ionisation converts ion to +ve ions
attract to negative plate
ions accelerate - increase kinetic energy of ions
pass through -ve plate
drift down chamber to detector
once reached they gain electrons from detector
lighter the mass- faster it arrives to the detector .

Question 20

molecular formula definition

Answer 20

actual number of atoms of each element in a compound .

Question 21

empirical formula definition

Answer 21

simplest whole number ratio of atoms of each element present in a compound .

Question 22

number of particles - equation

Answer 22

amount ( moles ) x Avogadro’s constant

Question 23

amount in moles - equation

Answer 23

mass in (g) divided by molar mass

Question 24

what is a solute ?

Answer 24

something that is dissolving

Question 25

what is a solvent ?

Answer 25

what the solute is dissolving in

Question 26

what is a solution ?

Answer 26

what it makes

Question 27

what does concentrated mean ?

Answer 27

a lot of solute per dm3

Question 28

what does dilited mean ?

Answer 28

a small amount of solute per dm3

Question 29

concentration equation

Answer 29

moles divided by volume

Question 30

how to go from cm3 to dm3

Answer 30

divide by 1000

Question 31

atom economy equation ?

Answer 31

mass of desired product divided by sum of molecular masses x100

Question 32

percentage yield equation :

Answer 32

actual divided by theoretical x 100

Question 33

how many subshells do we have ?

Answer 33

4 : S, P D F

Question 34

how many electrons does an orbital contain ?

Answer 34

2 e- per orbital

Question 35

how many orbitals in s subshell

Answer 35

i orbital with 2 e-

Question 36

how many orbitals in p subshell ?

Answer 36

3 orbitals with 6 e-

Question 37

how many orbitals in d subshell

Answer 37

5 orbitals with 10 e-

Question 38

how many orbitals in f subshell

Answer 38

7 orbitals with 14 e-

Question 39

define ionisation energy ?

Answer 39

energy needed to remove 1 mole of outer electrons from 1 mole of atoms in their gaseous state to form 1 mole of 1 + ions also in gaseous state

Question 40

what 3 factors affect IE ?

Answer 40

• atomic radius - as no e- increases - the distances between outer e- and nucleus increases , attraction decreases
• charge on nucleus - greater no protons = atomic radius decreases , force of attraction increases
  shielding- e- in outer shell repel by e- in inner shells = reduced attraction

Question 41

IE down group

Answer 41

atomic mass increases
no e- increases
more shielding takes place
repel
attraction decreases
NUCLEUR ATTRACTION is ioffset by these 2 factirs

Question 42

IE across period

Answer 42

no protons increase
nuclear charge increases
force of attraction increases
atomic radius decreases

Question 43

when does IE decrease

Answer 43

if goes from s orbital to p orbital
p orbital has higher energy level so less energy needed to remove e-

if e- are in pairs ~(in orbitals
) they will repel and shielding commences so IE is lower as attraction is lower .