Atoms and electrons Flashcards
Atomic number
number of protons in an atom of an element
proton number
Mass number
number or protons and neutrons in the nucleus of an element
nucleon number
Ion
electrically charged particle
formed by loss or gain of electrons
Isotopes
- atoms of same element
- same atomic number
- different mass number
- same number of protons
- different number of neutrons
Relative isotopic mass
mass of an atom of an isotope compared with 1/12th mass of carbon-12
Relative atomic mass
weighted mean mass of an element compared with 1/12th mass of carbon-12
First ionisation energy
energy required to remove 1 electron from each atom in 1 mol of gaseous atoms to produce 1 mol gaseous 1+ions
Orbital
- region of negative charge around the nucleus of an atom
- can hold max 2 electrons
- spin in opposite directions
Draw electronic configurations up to 3D
Draw S orbitals
Draw P orbitals
Ground state
- how element naturally exists
- electrons in lowest energy position
Evidence for electron shells
- Ionisation energy
- large jumps in energy
- electron is removed from shell nearer to nucleus
Relative molecular mass
average mass of one mol of of an element of compound
compared to 1/12 mass of c12
Mean weighted mass
Mean average of isotopes atomic masses
taking into account abundance