A. 2
The dash represents two electrons
<span>Chemical reactions at the Earth’s surface </span>
Answer:
Rb
Explanation:
Second ionization energy is the energy required for the removal of the second loosely bonded valence electron from an isolated gaseous atom.
The given elements:
Rb , Sr, Y and Zr
These are the elements of the fifth period.
The electronic configuration of Rb - ![[Kr]5s^1](https://tex.z-dn.net/?f=%5BKr%5D5s%5E1)
The electronic configuration of Sr - ![[Kr]5s^2](https://tex.z-dn.net/?f=%5BKr%5D5s%5E2)
The electronic configuration of Y - ![[Kr]5s^24d^1](https://tex.z-dn.net/?f=%5BKr%5D5s%5E24d%5E1)
The electronic configuration of Zr - ![[Kr]5s^24d^2](https://tex.z-dn.net/?f=%5BKr%5D5s%5E24d%5E2)
<u>When one electron is removed from Rb, the cation attains the noble gas configuration due to which the removal of second electron from Rb is very very difficult. Thus, Rb has the largest second ionization energy.</u>
The values of the second ionization of these elements are:
Rb = 2633 kJ/mol
Sr = 1064.2 kJ/mol
Y = 1180 kJ/mol
Zr = 1270 kJ/mol
Answer:
Zero
Explanation:
Hello,
The question require us to calculate the mass of nitrogen present in aluminium carbonate.
This can easily be calculated using Avogadro's number as a constant with some minor calculations but however in this case, we can't because there's no single atom of nitrogen present in aluminium carbonate hence we can't calculate the mass of nitrogen present in it.
Chemical formula of aluminium carbonate = Al₂(CO₃)₃.
From the above chemical formula, we can see that there's no single atom of nitrogen present in the formula hence the mass of nitrogen present in aluminium carbonate that contains 1.23×10²³ carbon atoms is zero.
Platinum:
850 Platinum: 85% platinum
950 Platinum: 95% platinum
900 Platinum: 90% platinum
Gold:
24 karat: 99.9% gold; the purest form.
22 karat: 91.7% gold
18 karat: 75% gold
14 karat: 58.3% gold
10 karat: 41.7% gold
