A, radium-228. Alpha radiation is essentially just two protons and two neutrons leaving the atom, causing the atomic number to drop by two (since the protons left) and the mass number to drop by four (since two neutrons and protons left).
Answer:
Mg ²⁺
Explanation:
Τhe metal loses electrons and in forming Mg²⁺ ,it loses 2 electrons and hence oxidized.
Mg(s) ⇒ Mg²⁺ + 2e⁻
Answer:
6 half-lives are required for the concentration of reactant to decrease to 1.56% of its original value.
Explanation:
Using integrated rate law for first order kinetics as:
Where,
is the concentration at time t
is the initial concentration
Given:
Concentration is decreased to 1.56 % which means that 0.0156 of
is decomposed. So,
= 0.0156
Thus,
kt = 4.1604
The expression for the half life is:-
Half life = 15.0 hours
Where, k is rate constant
So,

<u>6 half-lives are required for the concentration of reactant to decrease to 1.56% of its original value.</u>
Answer: Lexington and Concord
Explanation: The British were trying to find weapons and could not find them.
The number of protons in the nucleus for that element