MASS SPECTRA AND AMT OF SUBSTANCE

Question 1

What does mass spectometer do?

Answer 1

mass spectrometer gives correct information about relative isotopic mass and relative isotopic abundance.
- can be used to find relative molecular mass
- can be used to identify elements.

Question 2

how to calculate relative atomic mass from a mass spectrum?

Answer 2

• read the y axis and x axis and multiply them together.
• add up all and divide by 100%

Question 3

principal quantum number

Answer 3

each shell ina n electron is given a number which is called the principal quantum number. the farther a cell is from the nucleus, the higher its energy and a larger quantum number.

Question 4

electronic configuration

Answer 4

the number of electrons that an atom or ion has and how they are arranged is called electronic configuration.

Question 5

note

Answer 5

4s subshell comes before 3d subshell as it has a lower energy level eventho its quantum number is bigger.

Question 6

exceptions for electronic configuration

Answer 6

chromium and copper

Question 7

first ionisation energy

Answer 7

the energy needed to remove 1 electron from each atom in 1 mole of gaseous atom to form 1 mole of gaseous 1+ ion. it is measured in kj. mol -1

Question 8

first ionisation energy in a group

Answer 8

first ionisation energy decreases down a group.
- the more protons in the nucleus, the stronger the attraction.
- the greater the distance , the weaker the attraction.
- the more the shielidng, the lesser the attraction.

Question 9

first ionisation energy across a period

Answer 9

first ionisation energy generally increases across a period.
- nuclear charge increases - so attraction is increased- however shielding roughly stays the same.
- outer electron experiences a stronger attraction to the nucleus.

Question 10

why does first ionisation energy of aluminium doesnt follow the trend across period 3?

Answer 10

Unlike magnesium, whose electron is removed from the 3s sublevel, aluminium’s electron is removed from the 3p sublevel.
- This 3p sublevel is further away from the nucleus and also shielded by aluminium’s 3s electrons.
- So, it requires less energy to remove an electron from an aluminium atom

Question 11

why sulphur doesnt follow the trend for first ionisation energy across period 3?

Answer 11

Unlike phosphorus, whose electrons in the 3p sublevel are unpaired, sulfur has a pair of electrons in one of its 3p orbitals.
- Paired electrons repel each other more than unpaired electrons, so it requires less energy to remove an electron from a sulfur atom.

Question 12

successive ionisation energy

Answer 12

the ionisation energy that comes after the first ionisation energy is called successive ionisation energy.

Question 13

“Explain why the second ionisation energy of chlorine is higher than the first ionisation energy of chlorine.”, you just need to write

Answer 13

The second ionisation energy of chlorine is larger than its first ionisation energy because an electron must be removed from a positive ion, which requires more energy

Question 14

relative atomic mass

Answer 14

it is the ratio of average mass of an atom of an element to the average mass of an atom of c12

Question 15

relative molecular mass

Answer 15

is the ratio of average mass of a molecule to the average mass of an atom of c12.

Question 16

Empirical formula

Answer 16

empirical formula can be defined as the whole number ratio of atoms of each element of a compound.

Question 17

molecular formula

Answer 17

molecular formula can be defined as the actual number of atoms of each element in a compound.

Question 18

spectator ions

Answer 18

ions that are present in a solution but dont change during a recation.

Question 19

net ionic equation

Answer 19

An ionic equation where the spectator ions have been removed is called a net ionic equation.