Mendeleev organized his periodic table in order of increasing atomic number in 1869.
Answer:
Its helium
Explanation: Because teh effective nuclear charge holds the valence ectrons clos to the nuclues. the Atomic radius would decrease as you move from the led=ft and right of the perodic table
Answer:
HCN, weak acid
H⁺, Br⁻, strong acid
Explanation:
Hydrocyanic acid is a weak acid, according to the following equation.
HCN(aq) ⇄ H⁺(aq) + CN⁻(aq)
Thus, it should be written in the undissociated form (HCN).
Hydrobromic acid is a strong acid, according to the following equation.
HBr(aq) ⇒ H⁺(aq) + Br⁻(aq)
Thus, it should be written in the ionic form (H⁺, Br⁻).