Describe the nuclear model of an atom. [2] - CORRECT ANSWER-- Nucleus
containing of protons and neutrons.
- Surrounded by electrons in energy levels.
State the relative mass and charges of a proton [2]. - CORRECT ANSWER-Mass: 1
Charge: +1
State the relative mass and charges of a neutron. [2] - CORRECT ANSWER-Mass: 1
Charge: 0
Define atomic number (Z). [1] - CORRECT ANSWER-The number of protons in an
atom.
State the relative mass and charges of an electron. [2] - CORRECT ANSWER-Mass:
1/1840
Charge: -1
,Define mass number (A). [1] - CORRECT ANSWER-The number of protons and
neutrons combined in an atom
Define isotope. [1] - CORRECT ANSWER-Atoms with the same number of protons
but a different number of neutrons.
Describe the chemical properties of two isotopes of the same element. [2] -
CORRECT ANSWER--Same chemical properties.
-As same electron configuration.
State the uses of mass spectrometry: [4] - CORRECT ANSWER-- Identify elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
Why is mass spectrometry done in a vacuum? [1] - CORRECT ANSWER-Prevent
positive ions from colliding with molecules in the air.
Describe electrospray ionisation: [4] - CORRECT ANSWER-- Sample dissolved in
volatile solvent.
- Injected through a fine hypodermic needle giving a fine mist/aerosol.
- Tip of needle connected to positive terminal of a high voltage.
- Each molecule gains a proton as it leaves the needle.
,Describe acceleration: [2] - CORRECT ANSWER-- The positive ions are attracted to
a negatively charged plate and accelerate towards it.
- All ions accelerate forward so that they have the same kinetic energy, but reach
different velocities due to their varying masses. (lighter → faster)
Describe ion drift: [2] - CORRECT ANSWER-- Some of the ions pass through a hole
in the negatively charged plate, forming a beam of particles. They travel along the
'flight tube' towards the detector.
- As the ions are travelling at different speeds, they drift apart further.
Describe detection: [2] - CORRECT ANSWER-- When the positive ions hit the
negatively charged detection plate, they gain an electron.
- This generates a current, the size of which is proportional to the number of each
type of ion.
Describe data analysis: [1] - CORRECT ANSWER-The signal from the detector is
passed to a computer which generates a mass spectrum from the current.
What does each peak on the graph represent? [2] - CORRECT ANSWER-- Each
peak represents different isotope.
- Height gives relative abundance of each isotope.
Give the formula for relative atomic mass: [1] - CORRECT ANSWER-(sum of
abundances not 100)
, Describe where electrons are found. [3] - CORRECT ANSWER-- Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
Define orbital. [1] - CORRECT ANSWER-An orbital is a region within an atom that
can hold up to two electrons with opposite spins.
How many orbitals are there in...
a) an s sub-shell
b) a p sub-shell
c) a d sub-shell [3] - CORRECT ANSWER-a) one s orbital
b) three p orbitals
c) five d orbitals
Define highest energy electron. [1] - CORRECT ANSWER-The outer most electron
on an atom or ion.
What is stated by the Aufbau principle? [1] - CORRECT ANSWER-Orbitals of lower
energy are always filled first.
containing of protons and neutrons.
- Surrounded by electrons in energy levels.
State the relative mass and charges of a proton [2]. - CORRECT ANSWER-Mass: 1
Charge: +1
State the relative mass and charges of a neutron. [2] - CORRECT ANSWER-Mass: 1
Charge: 0
Define atomic number (Z). [1] - CORRECT ANSWER-The number of protons in an
atom.
State the relative mass and charges of an electron. [2] - CORRECT ANSWER-Mass:
1/1840
Charge: -1
,Define mass number (A). [1] - CORRECT ANSWER-The number of protons and
neutrons combined in an atom
Define isotope. [1] - CORRECT ANSWER-Atoms with the same number of protons
but a different number of neutrons.
Describe the chemical properties of two isotopes of the same element. [2] -
CORRECT ANSWER--Same chemical properties.
-As same electron configuration.
State the uses of mass spectrometry: [4] - CORRECT ANSWER-- Identify elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
Why is mass spectrometry done in a vacuum? [1] - CORRECT ANSWER-Prevent
positive ions from colliding with molecules in the air.
Describe electrospray ionisation: [4] - CORRECT ANSWER-- Sample dissolved in
volatile solvent.
- Injected through a fine hypodermic needle giving a fine mist/aerosol.
- Tip of needle connected to positive terminal of a high voltage.
- Each molecule gains a proton as it leaves the needle.
,Describe acceleration: [2] - CORRECT ANSWER-- The positive ions are attracted to
a negatively charged plate and accelerate towards it.
- All ions accelerate forward so that they have the same kinetic energy, but reach
different velocities due to their varying masses. (lighter → faster)
Describe ion drift: [2] - CORRECT ANSWER-- Some of the ions pass through a hole
in the negatively charged plate, forming a beam of particles. They travel along the
'flight tube' towards the detector.
- As the ions are travelling at different speeds, they drift apart further.
Describe detection: [2] - CORRECT ANSWER-- When the positive ions hit the
negatively charged detection plate, they gain an electron.
- This generates a current, the size of which is proportional to the number of each
type of ion.
Describe data analysis: [1] - CORRECT ANSWER-The signal from the detector is
passed to a computer which generates a mass spectrum from the current.
What does each peak on the graph represent? [2] - CORRECT ANSWER-- Each
peak represents different isotope.
- Height gives relative abundance of each isotope.
Give the formula for relative atomic mass: [1] - CORRECT ANSWER-(sum of
abundances not 100)
, Describe where electrons are found. [3] - CORRECT ANSWER-- Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
Define orbital. [1] - CORRECT ANSWER-An orbital is a region within an atom that
can hold up to two electrons with opposite spins.
How many orbitals are there in...
a) an s sub-shell
b) a p sub-shell
c) a d sub-shell [3] - CORRECT ANSWER-a) one s orbital
b) three p orbitals
c) five d orbitals
Define highest energy electron. [1] - CORRECT ANSWER-The outer most electron
on an atom or ion.
What is stated by the Aufbau principle? [1] - CORRECT ANSWER-Orbitals of lower
energy are always filled first.
