this notation is commononly used in chemistry where  represents the mass number, and  represents the atomic number of element .

To find the number of neutrons in each isotope, subtract the atomic number from the mass number.

Thus for , the number of neutrons is 67. This isotope has the most neutrons among the answer choices.

The number of protons for any atom is the same as the atomic number on the periodic table. Therefore, any isotope of copper will have 29 protons. Since the atom is neutral, the number of protons must be equal to the number of electrons. To find the number of neutrons, subtract the number of protons from the mass number to get 36 neutrons.

The charge on the ion is equal to the difference between the number of protons and electrons:

The element has 13 protons, which means its atomic number is also 13. Thus this element is aluminum.

The number of protons is equal to the atomic number on the periodic table. For lithium, this number is 3. Since this isotope is neutral, the number of electrons must be equal to the number of protons. To find the number of neutrons, subtract the number of protons from the mass number to obtain 3. The notation "lithium-6" indicates that the mass number of this isotope is 6.

The charge on the ion is equal to the difference between the number of protons and electrons.

The element has 35 protons, thus its atomic number is 35, which corresponds to bromine. 

Aufbau's Principle says that electrons fill lower energy levels first. Hund's Rule dictates that electrons fill singly if possible.

Individual order of reactants is a variable used to determine the rate of a reaction. Each reactant in the rate-limiting step of a reaction is assigned an order (typically zeroth, 1st, or 2nd). The reaction order is the sum of all individual orders. The rate of a reaction is defined as follows.

Where  is the rate of the reaction,  and  are reactants,  is rate constant, and  and  are individual orders. The reaction order of of this reaction would be . Note that the rate of a reaction depends on the concentration of reactants, rate constant, and the individual orders. It doesn’t depend on the reaction order.

The half-life is defined as the amount of time it takes to reduce the concentration of a substance (in this case a drug). After one half-life, 50% of the drug will be eliminated and 50% will remain. After the second half-life, half of the remaining drug (25%) will be eliminated; therefore, at the end of second half-life 75% of drug will be eliminated. To solve for this time, we can simply calculate the half-life and multiply it by 2.

To solve this question, we need to know the equation for half-life. It is stated that the reaction follows first-order; therefore, the half-life for a first order reaction is defined as

Where  is half-life and  is the rate constant. Since we are not given the rate constant we cannot calculate the half-life.

The half-life of a first order reaction is as follows:

Where  is half-life and  is the rate constant. The half-life only depends on the rate constant. Since rate constant is in the denominator, half-life and rate constant are inversely proportional. This means that half-life increases as rate constant decreases and vice versa. Concentration of reactants does not affect the half-life for a first order reaction.

Rate constant is a unique constant for each reaction that determines the rate of a reaction. It is one of several variables that determines the rate of reaction. As rate constant increases the rate of reaction increases. Rate constant depends on two main factors: temperature and activation energy. The rate constant increases as the temperature is increased. Recall that increasing temperature increases the kinetic energy of the molecules; therefore, an increase in temperature will increase the amount of molecules that reach activation energy. This will increase the rate constant and, subsequently, the rate of the reaction.

Rate constant increases as the activation energy is decreased. Activation energy is the energy hill that reactants must overcome to produce products. If the activation energy is decreased then it will be easier for reactants to overcome the energy hill and convert into products; therefore, decreasing activation energy will increase the rate constant and, subsequently, the rate of the reaction. Recall that catalysts speed up a reaction (increase rate of reaction) by lowering activation energy; therefore, catalysts increase the rate constant.