Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
Answer:
3.67 mol Cl
Explanation:
We need to convert g of Cl 2 to moles of Cl. First we divide 130 gCl2 by the molar mass (70.90 gCl2/mol) to find out how many moles of Cl2 do we have.
130 gCl2 x 
= 1.83 mol Cl2
Then we need to convert 1.83 mol de Cl2 to moles of Cl. We have 2 moles of Cl in every Cl2 molecule so we just need to multiply by 2.
1.83 molCl2 x 
= 3.67 molCl
Answer:
use the equation Mass= RFM*Moles
Explanation:
use your periodic table
and create a little table
The question is incomplete. Complete question is:
Which list represents the classification of the
elements nitrogen, neon, magnesium, and
silicon, respectively?
(1) metal, metalloid, nonmetal, noble gas
(2) nonmetal, noble gas, metal, metalloid
(3) nonmetal, metalloid, noble gas, metal
(4) noble gas, metal, metalloid, nonmetal
.................................................................................................................
Answer: The correct answer is option 2) nonmetal, noble gas, metal, metalloid
Reason:
1) Non-metal are bad conductors of electricity. Also non-metal are electronegative in nature. Hence, among the provided elements, nitrogen satisfied the criteria. Hence, it is a non-metal.
2) Noble gas are the elements which have completely filled outermost shell. Hence, among the provided elements, Neon satisfied the criteria.
3) Metal are good conductors of electricity. Also metal are electropositive in nature. Hence, among the provided elements, magnesium satisfied the criteria. Hence, it is a metal.
4) Metalloid have conductivity better than non-metals but poor than conductors. Hence, among the provided elements, Silicon satisfied the criteria. Hence, it is a metalloid.
