The Atom and Redox 2A Flashcards
isotopes
atoms of the same element with different numbers of neutrons and different masses
relative isotopic mass
the mass of an isotope compared with 1/12th the mass of an atom of carbon-12
relative atomic mass (Ar)
the weighted mean mass of an atom compared with 1/12th of the mass of an atom of carbon-12
what does a mass spectrometer tell you?
the relative isotopic masses and relative abundance for isotopes
in the spectrometer, atoms are converted to positive ions (usually 1+). If it is a 1+ ion, the mass to charge ratio (m/z) represents…?
the mass of the ion
first ionisation energy
the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions
write an equation for the 1st ionisation energy of sodium (Na)
Na(g) -> Na+(g) + e-
write an equation for the 2nd ionisation energy of calcium (Ca)
Ca+(g) -> Ca2+(g) + e-
What are the 3 factors which affect IE?
- charge on nucleus
- distance from nucleus
- electron shielding
affect of increased charge on nucleus on IE…
Increased IE
affect of increased distance from nucleus on IE…
Decreased IE
affect of increased electron shielding on IE…
Decreased IE
Why are p electrons easier to remove than s electrons? in 3p compared to 3s (Mg ->Al)
3p is further from the nucleus and there is more electron shielding so it is easier to remove
As you go down the group IE … because …
As you go down the group IE decreases because despite ^ in nuclear charge, there is an
^ electron shielding
^ distance from nucleus
Why is there a dip by Sulfer from Phosphorus? (or by oxygen from nitrogen)
there is electron repulsion as two electrons are in the same orbital in S whereas they are all single in P so it is slightly easer to remove. 3p4 electron easier to remove than 3p3 electron
As you go across a period IE … because …
As you go across a period IE increases because nuclear charge increases and distance from nucleus decreases as atomic radius decreases. Shielding remains the same.
What is the maximum number of electrons that can fill each type of subshell? (spdf)
s: 2
p: 6
d: 10
f: 14
What is the max no. electrons in the first four electron shells (energy levels)
2,8,18,32
what is an atomic orbital?
a region around the nucleus that can hold up to two electrons with opposite spins
shape of an s orbital
spherical
shape of a p orbital
dumb-bell
how many orbitals make up an s subshell?
1
how many orbitals make up a p subshell?
3
how many orbitals make up a d subshell?
5
orbitals fill in order of…
increasing energy
filling order of orbitals:
1s,2s,2p,3s,3p,4s,3d,4p,4d,4f
orbitals of the same energy are occupied by electrons … before pairing up
singly
when removing electrons remember
first in first out
an increase in ON number means the atom has been
oxidised
a decrease in ON number means the atom has been
reduced
the ON of any uncombined element eg. O2 is
zero
the oxidation number of fluorine is always
-1
the sum of the ON of each element is =
to the charge on the compound
the oxidation number of oxygen is (apart from peroxides or when bonded to fluorine)
-2
the oxidation number of all Group 1 ions
+1
the oxidation number of all Group 2 ions
+2
the oxidation number of hydrogen is (apart from when H- in metal hydrides)
+1
when an element has compounds/ ions with different oxidation numbers this should be represented using
roman numberals
oxidation is the … of electrons
loss
reduction is the … of electrons
gain
