Atoms and the periodic table
1. Give the number of protons, neutrons and electrons in the following
atoms or ions:
11B
80Br–
79Br+
2.
An isotope of the anion Cl– has a molar mass of 36.966 g mol–1.
Give the number of protons, neutrons and electrons per ion.
3.
The 11B isotope of boron accounts for 80.1% of boron while 10B
isotope accounts for the remainder. Estimate the average molar mass for
boron to three significant figures.
4.
List all possible values for the angular momentum quantum
number, l, for the electron shell with principal quantum number n = 3.
5.
How many orbital levels (subshells) have the principal quantum
number n = 4? Identify them using ns, np, nd, … notation.
6.
List all possible values for the magnetic quantum number ml for
a d orbital.
7. What is the maximum number of electrons that can be
accommodated in the following type of orbitals:
3p
3d
8.
Give the full electron configurations for the most stable states of
the elements below:
Be (Z = 4)
Ca (Z = 20)
Cu (Z = 29)
Ni (Z = 28)
9.
Consider the quantum number sets given below:
(a)
(b)
(c)
(d)
(e)
n
4
3
2
3
-1
l
2
1
2
1
0
ml
-2
1
-2
0
0
ms
1/2
-1/2
-1/2
1/2
1/2
Of the orbitals that are allowed:
(a) Which set is associated with the electron with the highest energy?
(b) Which electrons could be in the same orbital?
(c) Which electrons could be in the same shell?
(d) Which electron is in a d orbital?
10.
Which of the following electron allocations are (a) the ground
state, (b) an excited state, (c) are impossible?
11.
Which configurations represent (a) the ground state (b) an
excited state (c) are impossible?
(i)
(ii)
(iii)
(iv)
(v)
(vi)
[He]2s22p1
[He]2s13d1
[Ar]3s23d7
[Kr]5s24d105p36s2
[Kr]5s34d105p5
[Rn]7s24f146d27p1