Answer:
C = 4
N = 5
P = 5
O = 6
H = 1
Step-by-step explanation:
Valence number is the number of valence electron of an atom. It can be count through electronic configuration of an atom.
Oxygen is present in group 18.
Its atomic number is 8.
Electronic configuration:
O₈ = 1s² 2s² 2p⁴
In valence shell (2s² 2p⁴) there are six electron thus valence number of oxygen is six.
Carbon is present in group 14.
its atomic number is 6.
Electronic configuration:
C₆ = 1s² 2s² 2p²
In valence shell (2s² 2p²) there are four electron thus valence number of carbon is four.
Nitrogen is present in group 15.
Its atomic number is 7.
Electronic configuration:
N₇ = 1s² 2s² 2p³
In valence shell (2s² 2p³) there are five electron thus valence number of nitrogen is five.
Phosphorus is present in group 15.
Its atomic number is 15.
Electronic configuration:
P₁₅ = 1s² 2s² 2p⁶ 3s² 3p³
In valence shell (3s² 3p³) there are five electron thus valence number of phosphorus is five.
Hydrogen is present in group 1.
Its atomic number is one.
H₁ = 1s¹
Its valance number is 1.