Atomic Structure

Question 1

What is the formula for an ammonium ion?

Answer 1

NH₄⁺

Question 2

What is the formula for a hydroxide ion?

Answer 2

OH¯

Question 3

What is the formula for a nitrate ion?

Answer 3

NO3-

Question 4

What is the formula for a carbonate ion?

Answer 4

CO₃²⁻

Question 5

What is the formula for a sulfate ion?

Answer 5

SO₄²-

Question 6

What is the equation for concentration using moles and volume?

Answer 6

concentration= moles / volume

Question 7

What is an isotope?

Answer 7

A different form of the same element with the same number of protons but different number of neutrons

Question 8

Why do isotopes have the same chemical properties?

Answer 8

They have the same number of electrons

Question 9

What does mass spectrometry determine?

Answer 9

It determines relative atomic masses and relative formula masses

Question 10

What is the first step of mass spectrometry?

Answer 10

Ionisation

Question 11

What are the two different methods of ionisation?

Answer 11

electron impact and electrospray ionisation

Question 12

What happens during electron impact?

Answer 12

The sample being analysed is vaporised and then high energy electrons are fired at it from an electron gun. This knocks off one electron forming a +1 ion

Question 13

What size molecules is electron impact for?

Answer 13

For small molecules or atoms

Question 14

What happens during electrospray ionisation?

Answer 14

The sample is dissolved in a volatile solvent and injected through a fine hypodermic needle to give a fine mist (aerosol). The tip of the needle has high voltage and the particle is ionised by gaining a proton as it leaves the needle

X + H+ –> XH+

Question 15

What is the second step of mass spectrometry?

Answer 15

Acceleration

Question 16

What happens during acceleration?

Answer 16

The positive ions are accelerated using an electric field so that they all have the same kinetic energy. The velocity of each particle depends on its mass so lighter particles have a faster velocity and heavier particles have a slower velocity

Question 17

What is the third step of mass spectrometry?

Answer 17

Ion drift in the flight tube

Question 18

What happens during ion drift in the flight tube?

Answer 18

The positive ions travel through a hole in the negatively charged plate into a tube. The time of flight depends on a particle’s velocity which depends on its mass

Question 19

What are the time of flight equations?

Answer 19

t= d / v t=d x √m / 2KE KE=1/2MV^2 V= √2KE/M t= time d=length v= velocity m=mass KE=kinetic energy

Question 20

What is the fourth step of mass spectrometry?

Answer 20

Detection

Question 21

What happens during Detection?

Answer 21

The positive ion hits a negatively charged electric plate and they are discharged by gaining electrons. This generates a movement of electrons and an electric current is measured which is proportional to the relative abundance

Question 22

What are the main energy levels?

Answer 22

1 , 2 , 3 ,4

Question 23

How many orbitals does the sub level s have?

Answer 23

1

Question 24

How many orbitals does the sub level p have?

Answer 24

3

Question 25

How many orbitals does the sub level d have?

Answer 25

5

Question 26

How many orbitals does the sub level f have?

Answer 26

7

Question 27

How many electrons can 1 orbital hold?

Answer 27

2

Question 28

What is the spin rule?

Answer 28

Where 2 electrons in the same orbital must have opposite spin

Question 29

What is the Aufbau principle?

Answer 29

Atomic orbitals of lower energy are filled first

Question 30

What is Hund's rule?

Answer 30

Atomic orbitals of the same energy fill singly before starting pair

Question 31

What is the electron configuation of Cr?

Answer 31

1s2 2s2 2p6 3s2 3p6 4s1 3d5

Question 32

What is the electron configuration of Cu?

Answer 32

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Question 33

What is the rule with the 4s orbital?

Answer 33

If an electron enters the 4s orbital the energy increases to be greater then 3d

Question 34

What is ionisation energy?

Answer 34

Energy required to remove one mole of electrons from one mole of atoms in a gaseous state

Question 35

What is 1st ionisation energy?

Answer 35

energy required to remove one electron from each atom

Question 36

What is 2nd ionisation energy?

Answer 36

energy required to remove the second electron (not both)

Question 37

What happens to the ionisation energy down group 2 and why?

Answer 37

It decreases because as you go down group 2 the atoms get bigger and so the electrons are further way from the nucleus. Therefore there is a weaker attraction from the nucleus to the electron in the outer shell, so it is easier for it to be removed.

Question 38

What happens to the first ionisation energy across period 3 and why?

Answer 38

It generally increases because nuclear chage increases and the atoms get smaller which means there is a stronger attraction from the nucleus to the electron in the outer shell.

Question 39

What is an exception in the trend across period 3?

Answer 39

Al energy is lower than Mg because the electron lost from Al is from the p orbital while that lost from Mg is from the s orbital S energy is lower than P because in S the electrons are paired in the 3p orbital therefore the repulsion between electrons makes it easier to remove one of them

Question 41

What is weird when tranition metals become ions?

Answer 41

- They lose their 4s electrons before there 3d electrons