Answer: True.
Explanation.
The group 7A is actually named group 17.
That group is the halogens: F, Cl, Br, I, At, and Ts (Ts is one of the last elements discovered).
Those elements have 7 valence electrons (notice that it is the same number as the second digit in 17).
The atoms with 7 valence electrons will "easily" gain one electron to get the configuration of the next noble gas (8 valence electrons). That is why these elements gain electrons to form ions.
When atoms gain electrons form anions (negative ions). For example: F(-), Cl(-), Br(-), I(-).
Answer: 1.08 x 10^23 atoms
Explanation:
To find the no of moles in 35.12g of Au
no. of moles = mass/atomic mass
= 35.12/197
= 0.18 moles
1 mole of Au = 6.02 x 10^23
0.18 moles of Au = 0.18 x 6.02 x 10^23
=1.08 x 10^23 atoms
Answer:- 10 L of ethane.
Solution:- The given balanced equation is:

From this equation, ethane and oxygen react in 2:7 mol ratio, the ratio of volumes would also be same if they are at same temperature and pressure.
Since 14 L of each gas are taken, the oxygen will be the limiting reactant and ethane will be the excess reactant. Let's calculate the volume of ethane used:

= 
From above calculations, 4 L of ethane are used. So, excess volume of ethane left after the completion of reaction = 14 L - 4 L = 10 L
Hence, 10 L of ethane will be remaining.