topic 1 Flashcards
what is the structure of an atom
nucleus- protons and neutrons
electrons - orbit nucleus
what are the relative charges and masses of the sub atomic particles
relative charge
proton - 1
neurton - 0
electron - -1
relative mass
proton - 1
neutrons - 1
electrons - 1/2000
wwhat is the mass number and where is it on the periodic table
top number
protons and neutrons
what is the atomic number and where is it on the periodic table
bottom number
protons
what are ions
have a different number of electrons and protons
negative ions have gained electrons
positive ions have lost electrons
what is an isotope
elements with same number of protons but different number of neutrons
what is relative atomic mass
the weighted mean mass of an atom of an element compared to 1/12th of the mass of an atom of carbon-12
what is relative isotopic mass
the mass of an atom of an isotope compared to 1/12th of the mass of an atom of carbon-12
what is relative molecular mass
the mean mass of a molecule compared to 1/12th of the mass of an atom of carbon-12
how to work out relative atomic mass
total abundance
how to calculate isotopic mass
place x in isotopic mass you dont know
(abundance A X m/zA)+(abundance B X m/z B)
———————————
total abundance
how to predict mass spectra from % abundance
- write % as decimals
- create a table with isotope combinations
multiply decimal form abundances to get relative abundance from each molecule - any molecules which are the same add the aundances
- divide the relative abundances worked out by the smallest value to give whole number ratio to put on spectra
what is M+1 peak
molecular peak ion
same as Mr
what are the subshells with number of orbitals and number of electrons
s- 1 orbital 2 electrons
p- 3 orbitals 6 electrons
d- 5 orbitals 10 electrons
f- 7 orbitals 14 electrons
what subshells do shells 1 2 and 3 have and how many electrons can they hold
shell 1 - 1s- 2 electrons
shell 2 - 2s 2p- 8 electrons
shell 3 - 3s 3p 3d - 18 electrons
what is the shape of a s orbital
spherical
what is the shape of a p orbital
dumbells
what is spin pairing
when 2 electrons occupy 1 orbital they spin in opposite directions
how do electrons fill orbitalsand why
singly first the pair up due to electron repulsion
when are subshells most stable
when full or half full
where are the s d p and f blocks on the periodic table
s - group 1 and 2
d- transition metals
p - group 5 6 7 and 0
f - under d block
what is the electromagnetic spectrum
radiowaves
microwaves
infrared
vissible light
ultra violet
x rays
gamma rays
which side of the electromagnectic has the largest energy and frequcency of radiation
gamma rays side
what is line spectra evidence for and how
quantum shells
energy levels have discrete values and electrons can move from one shell to another
a line spectra shows the frequency of light given when a electron moves down
on line spectra where has the electron dropped to if lines are at ultraviolet
ground state
on line spectra where has the electron dropped to if lines are at visible light
n = 2
one line spectra where has the electron dropped to if lines are at infrared
n = 3
why is emission spectra evidence for quantum shells
they are diffined lines prove electrons exist in shells only and never between them
what is ionisation energy
min amount of energy required to remove 1 mole of electrons from 1 mole of atoms in gaseous state
what is the equation for the 1st ionisation energy Na
Na (g) –> Na^+ (g) + e^-
what affects the 1st ionisation energy
shielding - more shells between positive nucleus and negative electrons means weaker attraction = less energy
nuclear charge - more protons in nucleus the greater the attraction between outer electrons = more energy
atomic size - bigger the atom the further the outer electrons, attractive force reduces = less energy
what happens to ionisation energy down group and why
decreases
atomic radius increases
sheilding increases
what is successive ionisation energy
the removal of more than 1 electrons from the same atom
draw a graph a the successive ionisation of Mg and explain
gerneral increase - more positive ion
large increase after 1st 2 electrons as removing from a shell closer to nucleus
large increase after next 8 as new shell
what happens to atomic radii across a period
amd why
decreases across
increased nuclear charge- more protons pulls outer shell towards nucleus
extra electrons go into same shell
what is the trend in 1st ionisation energy across a period and why
increases
increased nuclear charge
similar sheilding
draw a graph to show 1st ionisation energy from Na to Ar
see flash card
what does the fact the 1st ionisation energy of Al lower than Mg provide evidence for
subshells
3p1
higher enrgy subshell further from nucleus
what does the fact that the 1st ionisation energy of S being similar to P provide evidence for
for electron repulsion
3p4
draw a graph for the melting points of Na ro Ar
see flash card
explain the bp of Na Mg and Al
metalic bonding
general increase as metal ions have increasing positive charge and delocalised electrons and have smaller ionic radius
explain the mp of Si
giant covalent
many covalent bonds
explain the mp of P
weaker simple molecular structure
weak london forces
expkain the mp of S
larger simple molecular structure
larger london forces
explain the mp of Cl
simple mocleular structure
smaller london forces
explain the mp of Ar
exists as individual atoms
smaller london forces
