Term 1 Flashcards
elements
types of atoms differing from each other by the number of subatomic particles
the Bohr model
an atom is a dense nucleus surrounded by a cloud of negatively charged electrons in distinct energy levels
> the atom is held together by electrostatic forces of attraction between the protons and electrons
subatomic particles
the particles within and surrounding the nucleus
electrons
negatively charged particles that travel at certain energy levels (but can jump)
similarities between electrons in same shell
similar distance from nucleus, and have similar energy
which electrons have the lowest energy?
the ones closest to the nucleus
for electrons to move…?
… energy must be absorbed or released
as the shell number increases…?
… energy levels get closer
electron configuration
how electrons are arranged around the nucleus
Aufbau Principle
- electrons enter orbitals of lowest energy
- orbitals within same energy level and sublevel all have equal energy
Pauli Exclusion Principle
- an atomic orbital can contain at most 2 electrons
- electrons in same orbital spin different directions
- shown as arrows (up and down)- must have different spins
Hund’s Rule
- every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied
- all electrons in singly occupied orbitals have the same spin
filling order
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
Noble Gas configuration
condensing electron configuration writing by using the closest previous noble gas
anion
- negative ion
- add electrons to the next available orbital
cation
- positive ion
- remove electrons from the last orbital
does the electron config change for ions
yes
what is the weird thing about ions in the d block
d group elements lose their 4s electrons before their 3d elements
isotopes
- different forms of elements with a different mass because of added or removed neutrons
allotropes
different forms of the same element
relative atomic mass
- the weighed average of the different isotopes of an element measured in a ratio
- takes into account the percentage abundance of all isotopes that exist of an element
other names for relative atomic mass
- atomic weight
- average atomic mass
Principal Energy Level (PEL)
- designated by the quantum number n
relative atomic mass formula
look in book
bonding atomic radius
- one half of the distance between covalently bonded nuclei
- the distance in picometres (pm) from the centre of the nuclei to the electrons in the outermost energy shell
electron shielding effect
the inner shell electrons repel the attraction of the valence electrons
atomic radius trend- group
as you go down a column, the atomic radius increases = stronger shielding effect
atomic radius trend- period
as you go across, L to R, atomic radius decreases = more electrostatic attraction (electrons put into same orbital)
smallest atomic radius’ in periodic table
noble gases
largest atomic radius’ in periodic table
alkali metal
ionic radius trend- metals
- lose electrons = more attraction
- ionic radius < neutral atomic radius
ionic radius trend- non metals
- gain electrons = less attraction
- ionic radius > neutral atomic radius
ionic size depends on?
- nuclear charge
- number of electrons
- orbitals in which electrons reside
metals tend to form? (cations/anions)
cations