Please help me l don’t understand please

Which best describes why nh4+ can form an ionic bond with cl-?

(1.6 × 10-19)(5.0 × 106) = c × 10d identify the missing numbers below to show the result of multiplying the numbers.

Melting and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.