SOMEONE, PLEASE HELP ME IT WAS DUE A WHILE AGO

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided

What causes the appearance of lines in a emission spectrum

F1.5 mol of nabh4 react, how many moles of b2h6 are formed? 2 nabh4(aq) + h2so4(aq) → 2 h2(g) + na2so4(aq) + b2h6(g)