Find the ions in the periodic table that have an electron configuration of nd8 (n = 3, 4,

The ions in the Periodic Table that have electron configuration of nd⁸ are: Cu⁺², Zn⁺², Ga⁺³, Ge⁺⁴, As⁺⁵, Se⁺⁶, Br⁺⁷, Pd⁺², Cd⁺², In⁺³, Sn⁺⁴, Sb⁺⁵, Te⁺⁶, I⁺⁷, Hg⁺², Tl⁺³, Pb⁺⁴, Bi⁺⁵, At⁺⁷.

Explanation:

To find the ions it is important to remember that  an ion is an atom with charge, if it has positive charge it is called cation, and if it has negative charge it is called anion.

In the Periodic Table there are only neutral atoms, so we do not find ions on it. Because of that, to find the ions that have an electron configuration of nd⁸ it is necessary look for atoms that have any d sublevel in its neutral atom electronic configuration.

Let's find them:

1st) Only atoms with an n level equal to 3, 4, 5 or 6 will have a d sublevel, that's why we have to look for them through periods 3, 4, 5 or 6 in the Periodic Table.

2nd) To find an ion that has 8 electrons in the d sublevel, we need to start looking for an atom with al least 29 or 30 electrons, because following the Moeller's Diagram (to order correctly the electrons in the sublevels of an atom) at level n=3 (the first one to have an d sublevel) we complete the configuration 1s², 2s², 2p⁶, 3s², 3p⁶, 4s² and then 3d⁹ or 3d¹⁰, so the total amount of electrons up to here is 29 or 30.

3rd) It is important to remember that an atom becomes an ion when the atom wins electrons or loses electrons, and we can consider this by paying attention to the Oxidation number (this number represents the possible charges that an atom could have if it loses electrons) in the Periodic Table.

For example:

- The Cooper atom (Cu) has 29 electrons, its electron configuration is [Ar] 4s¹ 3d¹⁰ and it has two possible oxidation numbers: 1 and 2. If an cooper atom loses 1 electron the electron configuration of its ion Cu⁺¹ will be [Ar] 4s¹ 3d⁹, but if it loses 2 electrons the electron configuration of its ion Cu⁺² will be [Ar] 4s¹ 3d⁸ and here we found the ion of cooper that has an electron configuration of nd⁸ with n=3.

- Another example it the Cadmium atom (Cd), it has 48 electrons, its electron configuration is [Kr] 5s² 4d¹⁰ and it has only one oxidation number: 2. So, if an cadmium atom loses 2 electrons, the electron configuration of its ion Cd⁺² will be [Kr] 5s² 4d⁸ with an electron configuration of nd⁸ and with n=4.

- Here are other ions that have an electron configuration of nd⁸: Zn⁺², Ga⁺³, Ge⁺⁴, As⁺⁵, Se⁺⁶, Br⁺⁷, Pd⁺², In⁺³, Sn⁺⁴, Sb⁺⁵, Te⁺⁶, I⁺⁷, Hg⁺², Tl⁺³, Pb⁺⁴, Bi⁺⁵, At⁺⁷.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.