1.2 - Atomic Structure Flashcards
What is the relative mass of an electron?
1/1837
Where are electrons found in atoms?
The shells of atoms
Atomic number definition
The number of protons in the nucleus of an atom.
Mass number definition
The total number of protons and neutrons in the nucleus of an atom.
Relative Atomic Mass (RAM) definition
The average (weighted mean) mass of an atom of an element relative to one-twelfth of the mass of an atom of carbon-12.
Relative Isotopic Mass (RIM) definition
The mass of an atom of an isotope of an element relative to one-twelfth of the mass of an atom of carbon-12.
Isotopes definition
Atoms which have the same atomic number but a different mass number (contain the same number of protons but different number of neutrons).
Relative Molecular Mass (RMM) definition
The average (weighted mean) mass of a molecule relative to one-twelfth of the mass of an atom of carbon-12.
Relative Formula Mass (RFM) definition
The average (weighted mean) mass of a formula unit relative to one-twelfth of an atom of carbon-12.
What is an orbital?
An orbital is a region within an atom that can hold up to two electrons with opposite spins.
How many electrons can fit in an orbital?
2
How many subshells are present in the s orbital?
1
How many subshells are present in the p orbital?
3
How many subshells are present in the d orbital?
5
How many subshells are present in the f orbital?
7
How many electrons are present in the s orbital?
2
How many electrons are present in the p orbital?
6
How many electrons are present in the d orbital?
10
How many electrons are present in the f orbital?
14
What is the chronological filling of orbitals in energy levels?
1s 2s 2p 3s 3p 4s 3d 4p 5s
What is Hund’s Rule?
Where electrons have choice between orbitals of equal energy, they will fill the orbitals singly as far as possible.
Although the 4S orbital is filled before the 3D orbital, upon being completed the 4S level rises to a higher energy level. Therefore when electrons are being removed, they are removed from 4S (blank) 3D.
Before
What is the shape of an s orbital?
Spherical
What is the shape of a p orbital?
Dumbbell
What group(s) in the periodic table belong to the s-block?
Group 1 and 2
What group(s) in the periodic table belong to the d-block?
Transition metals
What group(s) in the periodic table belong to the p-block?
Groups 3,4,5,6,7 and 0
What group(s) in the periodic table belong to the f-block?
Lanthanum series
Actinium series
What is meant by ‘s-block’?
The outer sub-shell to be filled is an s sub-shell
What is meant by ‘p-block’?
The outer sub-shell to be filled is a p sub-shell
What is meant by ‘d-block’?
The outer sub-shell to be filled is a d sub-shell
First ionisation energy definition
The energy required to convert one mole of gaseous atoms into one mole of gaseous ions with a single positive charge.
Second ionisation energy definition
The energy required to convert one mole of gaseous ions with a single positive charge into one mole of gaseous ions with a double positive charge.
Form an equation for the first ionisation energy of an element X.
X(g) —–> X+(g) + e-
Form an equation for the second ionisation energy of an ion X+.
X+(g) —–> X2+(g) + e-
What factors affect the size of ionisation energy?
- Nuclear charge
- Distance of the electron from the nucleus (atomic radius)
- Shielding effect of the inner electrons
- Stability of filled and half-filled subshells
What is the trend in ionisation energy across a period?
General trend shows an increase in ionisation energies across a period.
Due to:
• Increase in nuclear charge
• Decrease in atomic radius (as the electrons are pulled closer)
• Same number of shielding electrons (although the number of electrons increase they are only being added to the same energy level).
What is the trend in ionisation energy down a group?
Ionisation energy decreases as you go down a group.
This is due to:
• Increase in atomic radius
• Better shielding from inner radius
Third Ionisation Energy Definition
The energy required to convert one mole of gaseous ions with a double positive charge into one mole of gaseous with a triple positive charge.
