1:Atomic structure & the Periodic table Flashcards
What is the atomic number?
The number of protons in the nucleus of an atom.
What is the mass number?
The total number of protons & neutrons in the nucleus of an atom.
What is an isotope?
Atoms of an element with the normal amount of protons & electrons but a different number of neutrons.
What is the relative isotopic mass?
The mass of an atom of an isotope relative to 1/12th the mass of a carbon-12 atom.
What is the relative atomic mass?
The average mass of an atom of an element relative to 1/12th the mass of a carbon-12 atom.
What is the relative formula mass?
The average mass of a formula unit of a substance, relative to 1/12th the mass of a carbon-12 atom.
What is the relative molecular mass?
The average mass of a molecule of a substance, relative to 1/12th the mass of a carbon-12 atom.
How is mass spec done?
Sample is vaporised, then ionised, then accelerated, then deflected, then detected.
What is the first ionisation energy?
The energy required to remove one mole electron from one mole of gaseous atoms.
What effects ionisation energy?
Overall charge, nuclear charge, distance from the nucleus, shielding & sharing orbitals.
What is the trend in ionisation energy down a group?
Ionisation energy decreases due to the atoms becoming larger.
What is the trend in ionisation energy across a period?
Ionisation energy increases due to the increasing number of protons in the nucleus. (nuclear charge)
What is the atomic emission spectra?
Elements are put in 5kv electric field. Electrons gain energy & move up electron shells, as they move back down they give off light energy. The amount of light given off depends on how far the electron moves. This gives proof of quantum shells.
What is an orbital?
A region within an atom that can hold up to two electrons with opposite spin.
What is the order of orbitals?
1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p.
