Quiz 1 | Lewis Formulas
How many covalent bonds should form a neutral oxygen atom to follow the octet rule?
1
2
3
4
Electronic configuration of O (Z = 8): 1s2 2s2 2p4 ⇒ 6 valence electrons
A neutral oxygen atom needs 2 more electrons to follow the octet rule
What type of bond exists between the nitrogen atoms of N2H2?
Single bond
Double bond
Triple bond
Quadruple bond
Which of the following species has a triple covalent bond?
NH3
CO2
NO3-
NC-
What is the formal charge of boron atom in the molecule BF4-?
-2
-1
0
1
nb of valence electrons in a free boron atom: 3
nb of valence electrons in the bound boron atom of BF4-: 4
Formal charge = 3 – 4 = -1
Which of the following atoms could have an expanded valence shell?
Li
O
S
Ne
Valence shell of Li, O and Ne: n =2
Valence shell of S: n = 3
Expanded valence shell can happen only for atoms with a valence shell n 3
Which of the following atoms has the highest electronegativity?
F
O
H
Br
Electronegativity increases across a period and towards the top of a group in the periodic table