Atomic Structure Flashcards
Order of the atomic models
Dalton and Thomson’s model -> Rutherfords -> Bohr’s
Dalton’s model of the atom
Solid spheres made up of different elements
Thomsons model of the atom
Plum pudding model
Positively charged cloud with electrons
Rutherford’s model of the atom
Fired alpha particles at gold sheet
Most particles passed through and small number deflected
Concluded not a positive cloud but had positive nucleus surrounded by electrons
Bohr’s model of the atom
Electrons exist in shells
Each shell has fixed energy
Electron moves between shells by electromagnetic radiation being emitted or absorbed
Radiation has a frewuency
Calculate relative atom mass equation
isotopic masses x %
Find Mr of 75% 35Cl + 25% 37Cl
(35 x 75) + (37 x 25) / 100 (total percentages)
Relative mass and charge of proton neutron and electron
Mass:
Proton = 1
Neutron = 1
Electron = 1/2000
Charge:
Proton = +1
Neutron = 0
Electron = -1
What is an isotope
Different number of neutrons and mass
Same atomic number
Which has the largest atomic radius? Ar, Cl, Mg, Na
Na
Decrease from left to right of period
Increase from top to bottom
Which of these atoms has the smallest number of neutrons? 3H, 4He, 5He, 4Li
D
Top - bottom number = neutrons
Which requires the largest amount of energy?
A) He+ (g) -> He2+ (g) + e-
B) Li(g) -> Li+(g) + e–
C) Mg+(g) -> Mg2+(g) + e–
D) N(g) -> N+(g) + e–
A
+ -> 2+ means removing 2 electrons
He has 8 electrons in outter shell, so removing 2 takes most energy as its most stable
(Li only removing 1 and is in group 1, Mg in group 2 removing 2, N in group 5 removing 1)
Photochromic glass contains silver ions and copper ions. A simplified version of a redox equilibrium is shown below. In bright sunlight the high energy u.v. light causes silver atoms to form and the glass darkens.
When the intensity of the light is reduced the reaction is reversed and the glass lightens.
Cu+(s) + Ag+(s) clear glass -> Cu2+(s) + Ag(s) dark glass
Which one of the following is a correct electron arrangement?
A) Cu+ is [Ar]3d94s1
B) Cu is [Ar]3d104s2
C) Cu2+ is [Ar]3d84s1
D) Cu+ is [Ar]3d10
D
Ar is 18, Cu is 29
+ = -1 from its bottom number
Use reactant
Chlorine has two isotopes, 35Cl and 37Cl. The humber of molecular ion peaks in the mass spectrum sample of Cl2 is
A) 2
B) 3
C) 4
D) 5
B
Which one of the following is the electronic configuration of the strongest reducing agent?
A) 1s2 2s2 2p5
B) 1s2 2s2 2p6 3s2
C) 1s2 2s2 2p6 3s2 3p5
D) 1s2 2s2 2p6 3s2 3p6 4s2
D
Reducing agent loses electrons
Needs to be able to lose electrons easily
Has most shells and lowest in last shell
An atom in which the number of protons is greater than the number of neutrons is
A) 234U
B) 6Li
C) 3He
D) 2H
C
Top - protons (bottom number) = neutrons
Assuming that chlorine exists as two isotopes, and that hydrogen and carbon exist as one isotope each, how many molecular ion peaks will be shown in the mass spectrum of C4H6Cl4?
A) 2 B) 3 C) 4 D) 5
D
Chlorine has 3 peaks, hydrogen and carbon are one isotope so have 1 peak each
Which one of the following atoms has only two unpaired electrons in its ground (lowest energy) state?
A) helium
B) beryllium
C) nitrogen
D) oxygen
D
2 electrons in first shell
6 in second shell
Only 2 electrons are paired in outer shell if you draw it out, so it has 2 unpaired electrons
Which one of the following does not have a pair of s electrons in its highest filled electron energy sub-level?
A) H− B) Mg C) P3+ D) Ar
D
H = 2 in outer
B and C are both 12
So must be Ar
Which one of the following explains why boron has a lower first ionisation energy than beryllium?
A) A boron atom is smaller than a beryllium atom.
B) In beryllium all the electrons are paired in full sub-shells.
C) A beryllium atom has fewer protons than a boron atom.
D) In boron the 2p electron occupies a higher energy level than a 2s electron.
D
Just does
Which one of the following ionisations requires less energy than the first ionisation energy of oxygen?
A) S(g) → S+(g) + e−
B) O+(g) → O2+(g) + e−
C) N(g) → N+(g) + e−
D) F(g) → F+(g) + e−
A
Shielding and has more outer shells so easier to remove
Which atom has an incomplete sub-shell?
A) Be B) Ca C) Ge D) Zn
A
Sub shells go 1s2, 2s2, 2p2
Be is 1s2 2s1
Which one of the following is the electronic configuration of an element with a maximum oxidation state of +5?
A) 1s2 2s2 2p5
B) 1s2 2s2 2p6 3s2 3p1
C) 1s2 2s2 2p6 3s2 3p3
D) 1s2 2s2 2p6 3s2 3p6 3d7 4s2
D
Oxidation is loss, needs to lose 5 electrons MAX
Stable if it loses 5, if it loses anymore its not stable
Use the Periodic table to deduce the full electron configuration of calcium
1s2 2s2 sp6 3s2 3p6 4s2
Write an ionic equation, with state symbols, to show the reaction of calcium with an excess of water
Ca(s)+ 2H2O(l) Ca2+(aq) + 2OH–(aq) + H2(g)
State the role of water in the reaction with calcium
Oxidising agent
Write an equation to show the process that occurs when the first ionisation energy of calcium is measured
Ca(g) -> Ca+(g) + e–
State and explain the trend in the first ionisation energies of the elements in Group 2 from magnesium to barium
Trend: Decrease going down
Explanation: Ions get bigger/more shells
Weaker attraction of ion to lose electron (so it’s easier)
State the element in Period 3 that has the highest melting point. Explain your answer
Element: Silicon
Explanation: Strong covalent bonds which
Require a lot of energy to break these covalent bonds
State the element in Period 3 that has the highest first ionisation energy. Explain your answer
Element: Argon
Explanation: Largest number of protons so has a larger nuclear charge. Same amount of shielding.
Suggest the element in Period 3 that has the highest electronegativity value
Chlorine
Has 7 electrons in outer shell and needs one more to become stable
Name and draw the shape of CCl2
Shape: bent
Draw: C has one lone pair and 2 Chlorine’s attached
A naturally occurring sample of the element boron has a relative atomic mass of 10.8.
In this sample, boron exists as two isotopes, 10B and 11B
(i) Calculate the percentage abundance of 10B in this naturally occurring sample of boron.
10x + 11y / x + y = 10.8
Abundance of 10B is 20%
Explain, in terms of its structure and bonding, why nickel has a high melting point
Contains positive nuclei and delocalised electrons
With strong attraction metallic bonds
Why is nickel malleable and stretchable
Has layers of atoms that can slide over one another
Draw labelled diagram showing arrangement of particles in crystal of nickel. Include at least 6 particles.
3 circles on top of another 3 circles. With positive plus sign in middle. Has to be in exact layer identical on top and bottom, circles not drawn in gaps of circles below.
Give the full electron configuration of the Ni2+ ion
1s2 2s2 2p6 3s2 3p6 3d8 (4s0)
Balance the equation below and identify one substance that could react with both gaseous products
……NiCl2.6H2O(s) + …… SOCl2(g) ……NiCl2(s) + ……SO2(g) + ……HCl(g)
NiCl2.6H2O + 6 SOCl2 -> NiCl2 + 6 SO2 + 12 HCl
Write an equation for the formation of aluminium chloride from its elements.
2Al + 3Cl2 -> Al2Cl6
Draw and name the shape of the TlBr 2− ion
Name: Trigonal Bipyramid
Draw: Tl in middle, Br on top and underneath. 2 Br on right coming out like triangle. 1 Br coming straight out of left
Which change requires the largest amount of energy?
A) He+(g) -> He2+(g) + e-
B) Li(g) -> Li+(g) + e-
C) Mg+(g) -> Mg2+(g) + e-
D) N(g) -> N+(g) + e-
A
Closest to nuclei
Ionisation energy increases going across
what does an s orbital look like
circle
what does a p orbital looklike
infinity sign
how many p orbitals are there
3
one parallel
one horizontal
one diagnonal
Definition of first ionisation energy
energy required to remove first electron
definition of second ionisation energy
energy required to remove 2nd electron from 1+ ion
Nuclear charge trend across group 2
increases going across
more protons, more positive charge
Why does Be have higher energy than Boron
goes from 2s2 o 2p1, easier to remove electron from p orbital than from s
Why does oxygen have a lower ionisation energy than nitrogen
Nitrogen = 1s2 2s2 2p3
O = 1s2 2s2 2p4
Electron repulsion between two e- in p orbital causes decrease in ionisation energy. Easy to remove electron because it’s being repelled already.
Nitrogen has 3 electrons so fills up all 3 p orbitals equally, oxygen has a fourth so one p orbitals has 2 electrons in it
Oxygen’s electrons in one p orbital repel each other making it easier to remove an electron
Mass spectroscopy 4 stages
1) Electrospray ionisation
2) Acceleration
3) Ion drift
4) Detection
Mass spectroscopy electrospray ionisation
1) Sample dissolved in polar solvent and pushed through small nozzle at high pressure
2) High voltage applied so particles lose an electron
3) Ionised particles separated from solvent, leaving as gas made up of positive ions
Mass spectroscopy acceleration
1) Positive ions accelerated by electric field
2) All ions gain same kinetic energy
3) Ions with lower mass/charge ratio accelerate greater
Mass spectroscopy ion drift
1) Ions leave electric field with constant speed and kinetic energy
2) They drift through region with no electric field at same speed as they left electric field
3) Ions with lower mass and charge travel faster
Mass spectroscopy detection
1) Light ions reach detector in less time than those with higher mass and charge
2) Detector detects current reached when ions hit it and record how long it took to pass through spectrometer
