Atoms and Elements Review:
1. Complete the table:
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p6
Name
Symbol # Protons # Neutrons # Electrons Atomic #
Mass #
Carbon-12
C
6
6
6
6
12
Nickel
Ni
28
31
28
28
59
Bromine
Br
35
45
36
35
80
Copper
Cu
14
15
14
14
29
2.
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
q)
r)
s)
t)
3.
Complete the longhand electron configuration for:
Oxygen (8 electrons): 1s22s22p4
Argon (18 electrons): 1s22s22p63s23p6
Sodium (11 electrons): 1s22s22p63s1
Chromium (24 electrons): 1s22s22p63s23p64s23d4
Arsenic (33 electrons): 1s22s22p63s23p64s23d104p3
Krypton (36 electrons): 1s22s22p63s23p64s23d104p6
Strontium (38 electrons): 1s22s22p63s23p64s23d104p65s2
Silver (47 electrons): 1s22s22p63s23p64s23d104p65s24d9
Tin (50 electrons): 1s22s22p63s23p64s23d104p65s24d105p2
Cerium (58 electrons): 1s22s22p63s23p64s23d104p65s24d105p66s24f2
Rhodium (45 electrons): 1s22s22p63s23p64s23d104p65s24d7
Lead (82 electrons): 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p2
Francium (87 electrons): 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s1
Uranium (92 electrons): 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f4
Nobelium (102 electrons): 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f14
Ca2+ (18 electrons): 1s22s22p63s23p6
O2- (22 electrons): 1s22s22p63s23p64s23d2
P3-(18 electrons): 1s22s22p63s23p6
Na+ (6 electrons): 1s22s22p2
Al3+ (10 electrons): 1s22s22p6
Complete the shorthand electron configuration for:
a) Oxygen (8 electrons): [He]2s22p4
b) Argon (18 electrons): [Ne]3s23p6
c) Sodium (11 electrons): [Ne]3s1
d) Chromium (24 electrons): [Ar]4s23d4
e) Arsenic (33 electrons): [Ar]4s23d104p3
f) Krypton (36 electrons): [Ar]4s23d104p6
g) Strontium (38 electrons): [Kr]5s2
h) Silver (47 electrons): [Kr]5s24d9
i) Tin (50 electrons): [Kr]5s24d105p2
j) Cerium (58 electrons): [Xe]6s24f2
k) Rhodium (45 electrons): [Kr]5s24d7
l) Lead (82 electrons): [Xe]6s24f145d106p2
m) Francium (87 electrons): [Rn]7s1
n) Uranium (92 electrons): [Rn]7s25f4
o) Nobelium (102 electrons): [Rn]7s25f14
Charge
0
0
-1
0
4. Draw Aufbau diagrams for:
a)Hydrogen
b) Helium
c) Lithium
d) Carbon
e) Nitrogen
f) Oxygen
g) Chromium
h) Magnesium
i)
Iron
j) Cobalt
k) Ca2+
l) O2-
m) P-3
n) Na+
o) Al3+
5. What are isotopes? Give an example.
Isotopes are atoms of the same element (THE SAME ATOMIC NUMBER AND THE SAME
NUMBER OF PROTONS), but with different number of neutrons (and as a result, a different
mass number). For example, carbon – 12, carbon – 13, and carbon – 14.
6. If an element typically comes in three varieties with abundances of:
Mass (g/mol)
Abundance
45
18.4%
46
32.9%
47
48.7%
What would be the mass that would be recorded on the periodic table? Write the symbolic
representations for the isotopes of the element X.
Mass = 46.303 g/mol
45
46
47
nX
nX
nX (n= protons in this case of unknown atomic number)
7.
Give three IONS that have the electron configuration of 1s22s22p63s23p6.
S2-, Ca2+, Cl-, P3-, K+
8.
Identify all the trends:
9. Explain why atomic radius decreases moving across a period and increases moving down a
row.
There is a decrease in atomic radius moving from left to right across the periodic table because
there is an increasing nuclear charge due to the increase in PROTONS. This means that there is
a greater pull on the outer most electrons.
Moving down a group there is an increase in atomic radii. As the energy level increases and an
electron orbital is added to the atom outer electrons move away from the nucleus creating a
larger atom.
10.An element forms a negative ion when ionized. On what side of the periodic table is the
element located? Explain.
The element is located on the right side of the periodic table. Elements on the right side of the
periodic table (ex. Group 15 – group 17) become stable when they gain a full octet of electrons.
Therefore elements on the right side of the periodic table are more likely to gain an electron
rather than lose an electron. Elements on this side of the periodic table are closer to becoming
stable when they gain electrons, if they lose an electron they become less stable!
11. What is ionization energy?
Ionization energy is defined as the energy required to remove an electron from a gaseous
atom. Think of it as how strongly an atom’s nucleus holds onto its valence electrons. A
strong hold means high ionizations energy and low ionization energy indicates an atom loses
its outer electron easily.
12. Why does lithium have a low ionization energy.
Li: 520KJ/mol (1st IE), 7300KJ/mol (2nd IE)
Li is willing to lose one electron in order to become stable like He. We can see that as an atom
loses an electron it requires more energy to move the next electron. As atoms and ions become
stable it is almost impossible to strip an electron from the atom or ion because it requires high
ionization energy!
13. What is electron affinity?
Electron affinity is the change in energy when an electron is added to a gaseous atom or ion to
from a negatively charged ion.
Electron affinity increases across a period because more energy is released. The attraction
between the incoming electron and the nucleus becomes stronger when we have a smaller atomic
radius so more energy is released because it wants to add an electron.
Electron affinity decreases moving down a group because electrons become farther away from
the nucleus so there is less of an attraction.
14. Which element in each pair is more electronegative? Why?
a) K, As
b) N, Sb
c) Sr, Be
a) As is more electronegative than K because As wants to gain electrons and K wants to lose
electrons in order for both of the atoms to be as stable as possible.
b) N is more electronegative than Sb because Sb is larger, therefore it is easier for Sb to lose
electron and for N to gain the electrons.
c) Be is more electronegative than Sr because Sr is larger, therefore it is easier for Sr to lose
electrons and easier for Be to gain electrons.
15. Who is Dmitri Mendeleev?
Dmitri Mendeleev was a scientist who helped create the periodic table. He was different than the
other scientists because he determined the missing elements on the periodic table by looking at
the chemical and physical properties of the elements around it.
16. Where are the alkali metals in the periodic table? What trend do you notice when each metal
reacts with water?
The alkali metals are located in group 1 on the periodic table. The elements become more
reactive with water as you go down the group because as the valence electrons move further
from the nucleus they are more easily stripped from the atom. This causes them to react more
violently in water.
17. Draw the Lewis structure and Bohr diagram for the following: Si, Mg+, S-.
Si: 14 protons, 14 electrons, 14 neutrons
Mg+: 12 protons, 11 electrons, 12 neutrons
-1
Mg
S-: 16 protons, 17 electrons, 16 neutrons
18. Use your timeline!