Answer:
C. An 1s orbital
Explanation:
At the first energy level, the only orbital available to electrons is the 1s orbital, but at the second level, as well as a 2s orbital, there are also orbitals called 2p orbitals.
Answer : The correct option is, (a) Synthesis
Explanation :
Synthesis reaction : A chemical reaction where multiple substances or reactants combine to form a single product.
It is represented as,

Combustion reaction : A chemical reaction in which a hydrocarbon react with the oxygen to give product as carbon dioxide and water.
It is represented as,

Single replacement reaction : A chemical reaction in which the more reactive element replace the less reactive element.
It is represented as,

In this reaction, A is more reactive element and B is less reactive element.
Double replacement reaction : It is a type of chemical reaction where a positive cation and a negative anion of two reactants exchange places to form two new products.
It is represented as,

(X and A are the cations, Y and B are the anions)
The given reaction is, 
In this reaction, calcium combine with the chloride to form calcium chloride as a product.
Hence, the given type of reaction is a synthesis reaction.
Answer:
The charge on the metal is +2
Explanation:
Taking a good look at the compound zinc nitride, we will notice that it is made up of zinc and nitrogen.
Zinc has a common common oxidation state of +2 while nitrogen has a common oxidation state of -3. When the two atoms combine, the individual charges on them will be +2 for zinc and -3 for nitrogen according to their common oxidation states.
Hence the answer.
Answer:
1.14 × 10³ mL
Explanation:
Step 1: Given data
- Initial volume of the gas (V₁): 656.0 mL
- Initial pressure of the gas (P₁): 0.884 atm
- Final volume of the gas (V₂): ?
- Final pressure of the gas (P₂): 0.510 atm
Step 2: Calculate the final volume of the gas
If we assume ideal behavior, we can calculate the final volume of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
V₂ = P₁ × V₁/P₂
V₂ = 0.884 atm × 656.0 mL/0.510 atm = 1.14 × 10³ mL