Question

Which of the following is not a correct ionic formula unit?

BaO
Ca3N2
KCl
LiS2

Question 3(Multiple Choice Worth 2 points)

When nitrogen and aluminum form an ionic bond, what is the formula?
N2Al3
NAl
Al2N3
AlN

Question 4 (Essay Worth 3 points)

What is the formula of a compound formed between iodine (I) and aluminum (Al)?


Question 5(Multiple Choice Worth 2 points)

What is the charge of an oxide ion?
2+
3+
2-
3-

Question 6(Multiple Choice Worth 2 points)

Which of the following is a possible formula unit?
Li3B
ClO2
LiCl
PbN

Question 7(Multiple Choice Worth 2 points)

What subscripts are needed to complete the formula unit Li_N_?
1,1
3,1
1,3
3,3

Question 8 (Essay Worth 3 points)

What is the resulting formula unit when magnesium (Mg) and nitrogen (N) bond?


Question 9(Multiple Choice Worth 2 points)

What element gains three electrons to fill its valence energy level?
S
N
Al
C


number 4 and 8 are essays

Answer 1

1) LiS2
3) AIN
4) Al x 1 and I x 3 or Al I3
5) 2-
6) LiCl
7) 3,1
8) Mg3N2
9) N

Hope this helps! <3

Answer 2

Answer 1) Option D)
`LiS_(2)`

Explanation : The valency of Lithium is 1, which means lithium can lose one electron from its outermost valence shell and gain a positive charge on itself. It is combined with two moles of sulfur which is over satisfying the valency of lithium and is not abiding the rule of forming a molecular orbital.

Hence,
`LiS_(2)` is the answer for not being the correct ionic formula.

Answer 3) Option 4) AlN

Explanation : When aluminum is combining with nitrogen, aluminum has 3 valence electrons in its outermost shell. When nitrogen needs 3 electrons to form a stable bond with aluminum they share their electrons and achieve a stable state compound which is AlN. These 3 moles of Al needs 3 moles of N so, the chemical formula becomes AlN.

Answer 4)
`AlI_(3)`

Explanation : The formula of a compound formed between iodine (I) and aluminum (Al)will be
`AlI_(3)`. Here, one mole of Al is combined with 3 moles of Iodine as iodine has the valency as 1 and Aluminum has 3 as its valency. So, it would require 3 moles of iodine to combine with one mole of Al and form a stable compound.

Answer 5) Option C)
`2^(-)`

Explanation :
`2^(-)` It is seen that all Group 16 elements which are nonmetals gain two electrons to form an ion with a
`2^(-)` charge. So, when oxygen forms oxide ion the charge of the ion is
`2^(-)`. As, the atom of oxide ion gains two electrons to form complete octet.

Answer 6) Option C) LiCl.

Explanation : A formula unit in chemistry is defined as the empirical formula of any ionic or covalent network solid compound which is used as an independent entity for stoichiometric calculations. It is assumed to be the lowest whole number ratio of ions represented in an ionic compound. Lithium has one electron excess and Chlorine needs one electron attain the octet state. So, Li gives an electron to Cl and forms a compound LiCl.

Answer 7) Option B) 3,1

Explanation :The complete formula unit is
`Li_(3)N_(1)`. Lithium has one valence electron in its outermost valence shell and Nitrogen needs 3 electrons to be an octet. So, 3 moles of Lithium are needed to combine with one mole of Nitrogen and form
`Li_(3)N_(1)` which can be also written as
`Li_(3)N`.

Answer 8)
`Mg_(3)N_(2)`

Explanation : The formula unit when magnesium (Mg) and Nitrogen (N) bond is formed it will be
`Mg_(3)N_(2)`. As magnesium has the valency as 2 and nitrogen has 3 as its valency. Nitrogen is converted into nitride. As 3 moles of Mg will have 6 electrons in all and 2 moles of nitrogen will have 6 electrons. So, the formula unit will be
`Mg_(3)N_(2)`.

Answer 9) Option B) N

Explanation : Amongst the given choices only nitrogen will need 3 electrons to fill its valence energy shell and attain octet state. As the atomic number of nitrogen is 7, the electron distribution will be
`1s^(2)2s^(2)2p^(3)` so, it is easy or nitrogen to gain 3 electrons and fulfill the valence shell and be an octet state.