Question

1. Give the condensed ground state electron configuration for the following elements or ions.
   1. Cr³⁺

2. Sn

2. Draw the ground state orbital diagrams that represent the following elements or ions.
   1. O^2-

2. Se

4. Using only periodic trends (not exact values), arrange the following atoms in order of increasing atomic radius: P, As, S, F.

5. Consider S, Cl, and K and their most common ions.
   1. List the atoms in order of increasing size, using only periodic trends (not exact values).

2. List the ions in order of increasing size, using only periodic and ionic trends, not exact values.

6. Select one neutral atom and one ion for each of the following that would be considered isoelectronic.
   1. Mg²⁺

2. S^2-

3. Cr³⁺

7. Based on their positions on the periodic table (not exact values), list the following atoms in terms of decreasing ionization energy: Cl, As, Ne, Ba.

Answer 1

Valance electron: The electrons which are present in the outer most energy level are known as valance electron. This can be calculated by the group number of the element. Generally the group number is same as the valance electrons of any elements. Electron configuration: The arrangement of electrons in an atom by a superscript, in each sublevel is known as electron configuration. For example the d block elements have (n-1)d1-10 ns 0-2 electronic configuration The exited state: When one or more electrons are promoted to a higher energy level of electron configuration is known as the exited state. When; all electrons are paired in the compound or element then that is diamagnetic, while Para magnetism requires unpaired electrons. Cr The atomic number or number of electrons of Cr is 24, The Electron configuration of cr and Cr3+ are as follows: Cr-24: 152 252 2p 3s 3p%3d452 Cr3+ - 21: 1s? 2s²2p 3s 3p 3d 45° TJ]TJ] Tu] Inila D There are 3 un-paired electrons, thus it is para-magnetic. b. The atomic number or number of electrons of Sn is 50, which loses 2 electrons to form Snt. The numbers of electrons in sh+ is 50-2=48 The Electron configuration of Sn is as follows: Sn-50: 152 2s22 po 35°3p%3d10 452 4pô 4d10 5525p2 [Kr] 4dłº 5525p? The Electron configuration of Sn2+ is as follows: Sn2+ - 48: 152 2s22pó 3s23pº3d0 4s? 4p 4d0 5525pº [Kr] 40 552