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 formula $Al_2(CO_3)_3$

For aluminum ($Al$), the sub - script is 2. For carbon ($C$), considering the sub - script inside the parentheses and the outer sub - script, we have $1\times3 = 3$ carbon atoms. For oxygen ($O$), we have $3\times3=9$ oxygen atoms. The total number of atoms is $2 + 3+9=14$. So the answer to question 13 is A.

Step2: Analyze formula $Ca_3(PO_4)_2$

For calcium ($Ca$), the sub - script is 3. For phosphorus ($P$), we have $1\times2 = 2$ phosphorus atoms. For oxygen ($O$), we have $4\times2 = 8$ oxygen atoms. So the answer to question 14 is B.

Step3: Determine formula for 10 oxygen and 4 phosphorus atoms

The correct chemical formula notation has the element symbol first followed by the sub - script indicating the number of atoms. The formula for a compound with 10 oxygen and 4 phosphorus atoms is $P_4O_{10}$. So the answer to question 15 is A.

Step4: Recall diatomic elements

The diatomic elements are $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, $I_2$. Neon ($Ne$) is a noble gas and exists as single atoms. So the answer to question 16 is D.

Step5: Classify fluorine

Fluorine exists as $F_2$ in nature, which is a molecular element. So the answer to question 17 is A.

Step6: Identify non - molecular species

Carbon dioxide ($CO_2$) is a molecular compound, sulfur can form molecular structures, chlorine exists as $Cl_2$ (molecular), while neon ($Ne$) is a noble gas and exists as single atoms (not molecular in the same sense as the others). So the answer to question 18 is D.

Step7: Determine ionic compound formula

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

Answer:

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