Question

1. how many total atoms are in the formula al2(co3)3? a) 14 b) 8 c) 9 d) 12 e) none of the above 14) how many of each type of atoms are there in the formula ca3(po4)2? a) ca = 3, p = 1, o = 8 b) ca = 3, p = 2, o = 8 c) ca = 3, p = 1, o = 4 d) ca = 3, p = 2, o = 4 e) none of the above 15) what is the correct formula of a compound that has ten oxygen atoms and four phosphorus atoms? a) p4o10 b) o10p4 c) 10op4 d) 4po10 e) none of the above 16) which among the following elements does not exist as a diatomic molecule in nature? a) fluorine b) nitrogen c) hydrogen d) neon e) none of the above 17) fluorine is considered which of the following? a) molecular compound b) molecular element c) ionic compound d) atomic element e) none of the above 18) which of the following species is a molecular element? a) carbon dioxide b) sulfur c) chlorine d) neon e) none of the above 19) what is the formula for an ionic compound made of barium and nitrogen? a) ba2n4 b) ban c) ba3n2 d) ba2n3 e) none of the above

Explanation:

Step1: Analyze atoms in $Al_2(CO_3)_3$

For $Al_2(CO_3)_3$, there are 2 Al atoms. In the $CO_3$ group, there is 1 C and 3 O atoms, and since there are 3 $CO_3$ groups, there are 3 C atoms and 9 O atoms. Total atoms = 2 (Al) + 3 (C) + 9 (O)=14. So the answer to 13 is A.

Step2: Analyze atoms in $Ca_3(PO_4)_2$

In $Ca_3(PO_4)_2$, there are 3 Ca atoms. There are 2 P atoms (because of the sub - script 2 outside the $PO_4$ group), and there are 8 O atoms (4 O atoms in each $PO_4$ group and 2 $PO_4$ groups). So for 14, the answer is B.

Step3: Determine compound formula

A compound with four phosphorus atoms and ten oxygen atoms has the formula $P_4O_{10}$. So for 15, the answer is A.

Step4: Identify non - diatomic element

Fluorine ($F_2$), nitrogen ($N_2$), and hydrogen ($H_2$) are diatomic molecules in nature. Neon is a noble gas and exists as single atoms. So for 16, the answer is D.

Step5: Classify fluorine

Fluorine exists as $F_2$ in nature, which is a molecular element. So for 17, the answer is B.

Step6: Identify molecular element

Carbon dioxide is a molecular compound. Sulfur can exist as $S_8$ (a molecular element), chlorine exists as $Cl_2$ (a molecular element), and neon is an atomic element. Among the options, chlorine is a molecular element. So for 18, the answer is C.

Step7: Determine ionic compound formula

Barium has a + 2 charge ($Ba^{2 + }$) and nitrogen has a - 3 charge ($N^{3-}$). To balance the charges, the formula of the ionic compound is $Ba_3N_2$. So for 19, the answer is C.

Answer:

1. A. 14
2. B. $Ca = 3,P = 2,O = 8$
3. A. $P_4O_{10}$
4. D. Neon
5. B. molecular element
6. C. chlorine
7. C. $Ba_3N_2$