A1 Atomic structure Flashcards
Define an isotope
Atoms of the same element with different numbers of neutrons and different masses
same protons
same electrons
atoms of same element with same number of protons but different number of neutrons
Define Relative Atomic Mass
The average mass of an atom of an element compared to 1/12th the mass of Carbon-12 atom
Define Relative Isotopic Mass
The mass of an atom of a particular isotope of an element relative to 1/12th the mass of Carbon-12 atom
- can be found from mass spec
Define Weighted Mean Mass
The mean mass taking into account the relative abundances of the isotopes
What does the atomic number of an atom tell you?
Number of protons
What does the mass number of an atom tell you?
The number of neutrons and protons
How do you calculate the RFM given abundances and relative atomic masses?
abundance x masss + …
/
100
On a mass spectrometer, what do the peaks indicate?
Isotopes
What happens to all elements when in a mass spectrometer?
Develop a 1+ charge
How to calculate the RFM from a mass spectrometer, where the relative abundances don’t equal 100?
abundance x mass…. + …
/ total relative abundance
What peaks should be shown on mass spectrometers with diatomic elements?
All possible combinations of diatomic molecules, and all monotomic atoms
How many electrons occupy the first shell?
2
How many electrons occupy the 2nd shell?
8
How many electrons occupy the 3rd shell?
18
How many electrons occupy the 4th shell?
32
How many orbitals in s subshell?
1
How many orbitals in p subshell?
3
How many orbitals in d subshell?
5
How many electrons in ANY orbital?
2
Define an orbital
A 3D region of space around the nucleus, that can hold up to 2 electrons with opposite spins
What is the shape of an s orbital?
spherical
What is the shape of a p orbital?
dumbell - at right angles
What is the exception to the rule of subshells filling with increasing energy?
4s fills before 3d
How do electrons fill sub-shell orbitals as you go along the period?
Singularly, before doubling up in each orbital
Why is an element in the x block?
As its highest energy electrons occupy the x subshell
When writing electronic configurations, how should you write it when the 3d subshell is full?
Write it before 4s
What electrons are removed when positive ions form from d block elements?
4s are removed before 3d
Electronic configuration for chromium
Electronic configuration for copper
Define Ionic Bonding
The strong electrostatic attraction between positive and negative ions
Define an Ionic Lattice
A repeating pattern of oppositely charged ions
When drawing ionic lattices, what must be included in each circle?
Both the formula and the charge
Why do ionic compounds have high melting/boiling points?
Giant ionic lattice structure has lots of very strong ionic bonds. Lots of energy is required to break all the strong ionic bonds.
What ions are always soluble?
- Na+
- K+
- NH4+
- NO3-
State and explain the conductivity of solid ionic compounds
Does not conduct. Ions are fixed in position, not mobile and free to move around giant ionic grid-like lattice structure.
not able to move as mobile charge carries
State and explain the conductivity of aqueous and molten ionic compounds
Does conduct. Ions aren’t fixed in position, ions are mobile and free to move around the giant ionic grid-like lattice structure.
Define covalent bonding
The strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms
Define a Dative Covalent Bond
A covalent bond where both electrons are donated by one atom
What is used to measure the strength of a covalent bond?
Average bond enthalpy
Why does diamond/silicon have a very high melting/boiling point?
Each carbon atom makes 4 strong covalent bonds with other carbon/silicon atoms. Lots of energy is needed to break all the strong covalent bonds in the giant tetrahedral covalent lattice.
Why does graphite/graphene have a very high melting/boiling point?
Each carbon atom makes 3 strong covalent bonds with other carbon atoms. Lots of energy is needed to break all the strong covalent bonds in the giant covalent lattice structure.
State and explain the conductivity of diamond/silicon
Cannot conduct. Each carbon/silicon atom makes 4 strong covalent bonds with other carbon/silicon atoms. There are no delocalised electrons, or ions mobile and free to move around the giant tetrahedral covalent lattice structure.
State and explain the conductivity of graphite/graphene
Does conduct. Each carbon/silicon atom makes three strong covalent bonds with other carbon atoms. There is one delocalised electron per atom mobile and free to move around the giant covalent lattice structure.
Why is graphite soft?
Layers of carbon atoms are held together by weak forces of attraction. Layers are able to slide over each other.
Which giant covalent structures are soluble?
None of them
Why do simple molecular substances have a low boiling point?
Molecules held together by weak intermolecular forces. Not a lot of energy is needed to overcome the weak intermolecular forces that act between molecules.
State and explain the conductivity of simple molecular substances
None conduct as all the molecules are neutral. As there’s no delocalised electrons or ions present.
Define Metallic Bonding
Strong electrostatic attraction between a lattice of cations and a sea of negatively charged delocalised electrons
Why do metallic compounds have high melting/boiling points?
There are lots of strong metallic bonds in the giant metallic lattice structure. Lots of energy is required to break all the strong metallic bonds.
State and explain the conductivity of metals in all states
Conducts in all states as the sea of delocalised electrons are mobile and free to move around the giant metallic lattice structure.
When are metallic substances soluble?
Never
draw a linear molecule
draw a trigonal planar molecule
draw a tetrahedral molecule
draw a trigonal pyramidal molecule
draw an octahedral molecule
draw a trigonal pyramid molecule (Nh3)
draw a bent molecule (h20)
What are the relative repulsions of lone electron pairs and bonded electron pairs?
Lone pairs repel more than bonded pairs
How to write an answer, comparing bond angles?
State the number of bonded and lone pairs of each molecule. Lone pairs repel more strongly than bonded pairs. Bonded electron pairs repel equally.
Define electronegativity
The ability of an atom to attract the bonding electrons in a covalent bond
What is the most electronegative element?
Fluorine
How to determine what element is more electronegative?
Whatever is closest to fluorine in the periodic table
In a covalent bond, which atom do the electrons move closer to?
The more electronegative atom
How to explain if this molecule is or isn’t polar?
Has polar bonds. Molecule is symmetrical. Dipoles cancel out. Non-polar.
How to explain if this molecule is or isn’t polar?
Has polar bonds. Molecule isn’t symmetrical. Dipoles don’t cancel out. Polar.
Where do all intermolecular forces act?
Between molecules
In what molecules do London forces occur?
In every molecule (NOT giant covalent)
Why as molecules get larger, do their boiling points increase?
More electrons. Stronger London forces. More energy required to break London forces.
How are London forces induced?
Electrons move randomly in molecule. Creates a temporary dipole in the molecule. Induces temporary dipoles in neighbouring molecules.
Describe a permanent dipole force
Polar molecules have dipoles. Dipoles interact to form the dipole-dipole force.
Between what molecules does hydrogen bonding occur?
One lone pair of fluorine, oxygen or nitrogen and hydrogen of another molecule
What is the relative strength of the different intermolecular forces?
- Hydrogen bonding strongest
- Permanent dipole-dipole forces
- London forces
draw a hydrogen bonding diagram for two water molecules
What must be included in all hydrogen bonding diagrams?
- Lone pairs
- Dipoles
- Hydrogen bond
Describe and explain the anomalous properties of ice - relatively high melting point
Hydrogen bonding is very strong, so lots of energy needed to overcome it
Describe and explain the anomalous properties of ice - ice is less dense than water
Water molecules held apart in an open lattice structure by hydrogen bonds
State and explain the solubility of non-polar substances in non-polar solvents
Soluble. IMF’s form between molecules in solvent and molecules in solute. Weakens the IMF’s in the simple molecular solvent.
State and explain the solubility of polar substances in non-polar solvents
Insoluble. Attraction between molecules in solvent and ions in ionic lattice not strong enough to break ionic bonds in ionic lattice.
State and explain the solubility of polar substances in polar solvents
Soluble. Polar bonds in solute attract polar bonds in solvent.
2BP
linear 180
x3BP
trigonal planar 120
X2BP and X1LP
bent v 120
X4BP
tetrahedral 109.5
X3BP x1LP
trigonal pyramidal 107
X2BP x2LP
bent v 104.5
X5Bp
trigonal bipyrmaidal 120
X4Bp X1P
trigonal pyramidal 119, 89
X3Bp x2Lp
trigonal planar 120, 89
X6Bp
octahedral 90
x5BP X1LP
Square pyramidal 89
x4bp x2lp
square planar 90
linear 180
2BP
trigonal planar 120
x3BP
bent v 120
X2BP and X1LP
tetrahedral 109.5
X4BP
trigonal pyramidal 107
X3BP x1LP
bent v 104.5
X2BP x2LP
trigonal bipyrmaidal 120
X5Bp
trigonal pyramidal 119, 89
X4Bp X1P
trigonal planar 120, 89
X3Bp x2Lp
octahedral 90
X6Bp
Square pyramidal 89
x5BP X1LP
square planar 90
x4bp x2lp
which block does mg belong to
s block
highest energy electrons are in an s sub shell/ orbital
CU 2+ ion electron structure
1s2 2s2 2p6 3s2 3p6 3d9
Si is
giant covalent
p s and cl
simple molecular
Different isotopes of antimony have the same chemical properties
same number of electrons in outer shell
systematic name for fe2o3
Iron (III) oxide
bonding pairs
repel
lone pairs
repel more than bonding pairs
isotope defintion
same element
same protons and electrons
different neutrons
sulfide vs sulfate
ide= s 2-
ate- so4 2-
shape around carbon atoms in graphene
trigonal planar
which is not a neutration reaction
acid + metal
neutralisation reaction
produces water
metal oxide + acid
salt and water
polar
not symmetrical bonds
which substance has London forces in solis state
molecules
- not giant covalent
more branching
- decreases Bp
- more surface contact
- weaker London forces
- less energy to break weak London forces
lone pairs..
repel more than bonding pairs
bent v shape
104.5
Si is
giant covalent
ive sign
means more electronegative
London forces
between moleucles
relative atomic mass
the average mass of an atom relative to 1/12 of the mass of an atom of carbon - 12
