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
