Answer:
The atomic mass is the average number of protons and neutrons for all natural isotopes of an element. It is a decimal number.
Explanation:
Atomic Mass and Mass Number Example
:
Hydrogen has three natural isotopes: 1H, 2H, and 3H. Each isotope has a different mass number.
1H has 1 proton. Its mass number is 1. 2H has 1 proton and 1 neutron. Its mass number is 2. 3H has 1 proton and 2 neutrons. Its mass number is 3. 99.98% of all hydrogen is 1H 0.018% of all hydrogen is 2H 0.002% of all hydrogen is 3H Together, they give a value of atomic mass of hydrogen equal to 1.0079 g/mol.
The answer is d the inflation scale
Answer : The isoelectronic groups are:



Explanation :
Isoelectronic : It is defined as the compound or molecule having the same number of electrons and the same number of electronic structure.
- The element is helium. The number of electrons are 2.
- The element is beryllium. The number of electrons are 4. The number of electrons in
= 4 - 2 = 2 - The element is lithium. The number of electrons are 3. The number of electrons in
= 3 - 1 = 2 - The element is nitrogen. The number of electrons are 7. The number of electrons in
= 7 + 3 = 10 - The element is neon. The number of electrons are 10.
- The element is sulfur. The number of electrons are 16. The number of electrons in
= 16 + 2 = 18 - The element is magnesium. The number of electrons are 12. The number of electrons in
= 12 - 2 = 10 - The element is titanium. The number of electrons are 22. The number of electrons in
= 22 - 4 = 18 - The element is potassium. The number of electrons are 19. The number of electrons in
= 19 - 1 = 18
The isoelectronic groups are:


