Which of the following is a weak acid?

The noble-gas electron configuration for ₂₈Ni²⁺ is:

The molecular formula of a compound with a molar mass of 90.04 and with empirical formula CHO₂ is:        H = 1.008, C = 12.01, O =16

The reaction that will take place when a strong acid (H⁺) is added to a buffer solution of NH₃ / NH₄⁺ is:

How many mL of water must be added to 200 mL of 6.0 M NH₃ to dilute the solution to 1.5 M?

The Lewis structure for N₂ that satisfies the octet rule is:

Calculate the hydrogen ion concentration for a solution if the pH is 4.6

Which one of the following orbitals is NOT allowed?

The notation for the subshell with n = 4 and l = 3 is