Answer:
ATOMIC number of element A is 3
Explanation:
Atomic number is the same as number of protons of an element.
according to the periodic table, Lithium is the element with 3 protons in its neutral state and it's atomic number is 3.
Try adding spaces next time! That's iodine. Check all of the numbers to make sure all of the orbitals are filled, then find the ones which aren't. In this one, only the 5p5 subshell isn't full. 5p5 is the fifth row on the right side, count across the nonmetals and metalloids until the fifth one (a halogen). That's iodine, and that's your answer!
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.
Answer:
See below
Step-by-step explanation:
You won't see much happening. The solution is saturated, so the salt will fall to the bottom of the container and sit there. It will not dissolve.
However, at the atomic level, Na⁺ and Cl⁻ ions are being pulled from the surface of the crystals and going into solution as hydrated ions. At other places, Na⁺ and Cl⁻ ions are returning to the surface of the crystals.
The process is
NaCl(s) ⇌ Na⁺(aq) + Cl⁻(aq)
The rates of the forward and reverse processes are equal, so you see no net change.
To determine what gas is this, we use Graham's Law of Effusion where it relates the rates of effusion of gases and their molar masses. We do as follows:
r1/r2 = √(M2 / M1)
Let 1 be the the unkown gas and 2 the H2 gas.
r1/r2 = 0.225
M2 = 2.02 g/mol
0.225 = √(2.02 / M1)
M1 = 39.90 g/mol
From the periodic table of elements, most likely, the gas is argon.