Answer:
Na= 1, Ar= 8, V= 5, F= 7
Explanation:
You can determine the number of valence electrons in an element by looking the the group/column # on the periodic table. Elements in the same family/ group are organized by columns (vertical). Elements in the same column have the same number of valence electrons (electrons of the outermost shell) and consequently similar properties.
Simply put, GROUP #= # VALENCE E-
There are exceptions to this, especially when determining the amount of valence electrons in elements that are in a compound or in transition metal elements. For transition metals (that have different oxidation states- different # of valence electrons for the same element) I’d just look it up
Answer:
A - 3
B - 6
Explanation:
The valency of hydrogen atom is +1
The valancy of an atom of other element combining with the hydrogen atom can be determined from the number of associated hydrogen.
when H combines with A, three atoms of hydrogen are used. Thus the valency of element A is -3
Now B combines with two molecules of A whose valency is -3
The valency of B would be twice the valency of element A i.e 6
if hydrogen combines with B, then the compound formed will be BH6
Question:
1. (NH)2CrO
a) Number of moles of H:
b) Number of moles of N:
Answer:
a) Number of moles of H: 2
b) Number of moles of N: 2
Explanation:
The 
is ammonium Chromate which is monoclinic and yellow Crystal that is formed due to the reaction of ammonium Hydroxide and ammonium di-chromate. It is used as catalyst, corrosion inhibitor as well as analytical inhibitors.
Question:
2. Ag.SO.
a) Molar Mass:
b) Percent Composition of Ag:
c) Percent Composition of S:
d) Percent Composition of O:
Answer:
a) Molar Mass: 155.93 Kg
b) Percent Composition of Ag: 69%
c) Percent Composition of S: 20.5%
d) Percent Composition of O: 10.2%
Explanation:
Molar mass = molar mass of Ag + molar mass of S + molar mass of O
=>107.87+32.06+16
=> 155.93 Kg
Percent Composition of Ag
= 
= 
= 0.69 \times 100
= 69%
Percent Composition of S:
= 
=
= 0.205 \times 100
= 20.5%
Percent Composition of O:
= 
= 
= 0.102 \times 100
= 10.2%
It is known as the medium
Basic. Hope I helped. Have a great day.
(I may be wrong. If wrong I'm deeply sorry.)
