Se2- has 34 protons and 36 electrons so it gets a 2- charge.
Answer:
Argon {Ar}
Explanation:
The noble gas used for a condensed electron configuration is the one before the element which you are configuring.
In this case, the element (Mn) is manganese
The noble gas that is before this element is Argon which is the row above it
so your configuration would be {Ar} 3d^5 4s^2
Answer: 22g of chlorine would be needed to carry out this synthesis reaction
Explanation:
A synthesis reaction is one in which two or more than two elements combine together to forma single product.

The atoms present in the reactants are found on the product side. According to the law of conservation of mass, the number of atoms on both sides of the arrow must be same as the total mass must be conserved.
15 grams of sodium reacts with 22 grams of chlorine to yield 37 grams of sodium chloride. Thus 22g of chlorine would be needed to carry out this synthesis reaction.