Which of these pairs of elements have the same number of valence electrons?

hydrogen (H) and helium (He)

sodium (Na) and potassium (K)

carbon (C) and oxygen (O)

boron (B) and beryllium (Be)

Put the moon phases in order from first to last phase. A. B, C, A, D B. A, B, C, D C. D, B, C, A D. A, C, B, D

Blank can be made in the field or in the laboratory

Which type of particle retains the identity of an element during a chemical reaction?

What is needed in all chemical reactions in cells

Just as earth moves around the sun, the moon revoles around the earth. About how many earth days does it take for the moon to travel around the earth?

Which of the following quantum number combinations is not allowed in an atom? A. n = 2, l = 1, mr = - 1 B. n = 1, l = 1, m = 0 C. n = 8, l = 5, m = - 4 D. n = 6, l = 3, m = 2

13. Adding thermal energy to a gas at constant pressure will cause

A 3 ml volume of a solution containing an unknown concentration of hcl is added to 7 ml of water. it is then determined that the concentration of the hcl in the diluted solution is 630 mm. what was the concentration of hcl in the original solution?

How do you find the ph of water

How many total electron will fit in the 1st energy level