Which element has the same number of energy levels as aluminum (al) and the same number of valence electrons as calcium (ca)? a. beryllium b. sodium c. potassium d. magnesium

Asmall amount of a solid is added to water. the observation made after fifteen minutes is shown in the figure. which of these solids has been probably added to water? a) oil b) sand c) sugar d) wood chips

What is a difference between a mixture of elements and a mixture of compounds

How many moles of no2 will form when 3.3 moles of cu are reacted with excess hno3?