THE ATOM AND REDOX 2A Flashcards
Definition of atomic number
The number of protons in the nucleus of one atom of an element
Definition of an isotope
An atom of the same element that has the same number of protons but different number of neutrons
How to work out the mass number
The number of protons plus the number of neutrons
Definition of relative isotopic mass
The mass of one atom of an isotope compared to 1/12 the mass of one atom of carbon-12
Why is carbon-12 the standard
It can be obtained in an isotopically pure state and is unreactive
Definition of relative atomic mass
The weighted average mass of one atom of an element compared to 1/12 the mass of one atom of carbon-12
Definition of relative molecular mass (Mr)
The weighted mean mass of a molecule compared to 1/12 the mass of 1 atom of carbon-12
Definition of relative formula mass (Mr)
The weighted mean mass of a formula unit compared to 1/12 the mass of 1 atom of carbon-12
Definition of 1st ionisation energy
The amount of energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form one mole of gaseous 1+ ions
What are shielding electrons?
The electrons between the nucleus and other electron shells
State and explain the general trend of first ionisation energy across period 2
The IE increases. The charge in the nucleus increases because the proton number increases and the number of shielding electrons stays the same therefore the overall electrostatic attraction is stronger so the IE is larger. The atomic radius is also slightly smaller.
How many s orbitals are there?
1
How many p orbitals are there?
3 - px, py, pz
How many d orbitals are there?
5
How many f orbitals are there?
7
What is the term used for subshells that are of identical energy?
Degenerate
Definition of oxidation
loss of electrons/gain of oxygen/loss of hydrogen
Definition of reduction
gain of electrons
Definition of oxidising agent
A reagent that oxidises another species and is reduced in the process
Definition of reducing agent
A reagent that reduces another species and is oxidised in the process
What is the term used to describe when the same substance is both reduced and oxidised?
Disproportionation
Definition of orbital
Region of space that can hold up to 2 e- with opposite spin (and the same energy)
Rules of oxidation number: Group 1 elements
Have an O.N of +1
Rules of oxidation number: Group 2 elements
Have an O.N of +2
Rules of oxidation number: Fluorine atoms
Have an O.N of -1
Rules of oxidation number: Oxygen atoms
Have an O.N of -2 except when in a peroxide
Rules of oxidation number: Hydrogen atoms
Have an O.N of +1 except when in a hydride
Definition of molar mass
The mass per mole of a substance. The units of molar mass are g mol⁻¹
