Answer:
3. The proton number is 15.
Explanation:
Phosphorus, P is the element with the atomic number = 15. The atomic number = Number of protons. That means:
3. The proton number is 15.
Now, the number of protons = Number of electrons = 15.
And, nucleon number = Number of protons + number of neutrons. The must abundant phosphorus atom contains 16 neutrons and nucleon number is: 15+16 = 31.
Thus, we can know which statement is true.
Answer:

Explanation:
A chemical reaction describes the reaction between reactants to produce products.
A chemical equation is represented as a reactant present on the left-hand side of the equation if two or more reactants are present they are separated by the "plus" sign.
On the right side of the equation product is written and if more than one product is formed then these are separated by "plus" sign as in the reactants.
The reactant and the products are separated by an arrow, the head of arrow is in the direction of the product when the reaction is irreversible.
In the case of reversible reactions or chemical reactions that are present in equilibrium, the reactant and product are separated by a double-headed arrow.
Answer:
B and C
Explanation:
Selective breeding is a procedure that involves the purposeful breeding of selected parents in order to give rise to offsprings with desired traits. Selective breeding procedure has its own advantages, which includes the ability to produce more animal products such as milk, meat etc, however, it has disadvantages.
The disadvantages include that:
- Selectively bred animals are more likely to have some health problem
- Some desirable traits become more common in a population.
Answer :
(a) Reaction at anode (oxidation) :
(b) Reaction at cathode (reduction) :
(c) 
(d) Yes, we have have enough information to calculate the cell voltage under standard conditions.
Explanation :
The half reaction will be:
Reaction at anode (oxidation) :

Reaction at cathode (reduction) :

To balance the electrons we are multiplying oxidation reaction by 4 and then adding both the reaction, we get:
Part (a):
Reaction at anode (oxidation) :

Part (b):
Reaction at cathode (reduction) :

Part (c):
The balanced cell reaction will be,

Part (d):
Now we have to calculate the standard electrode potential of the cell.


For a reaction to be spontaneous, the standard electrode potential must be positive.
So, we have have enough information to calculate the cell voltage under standard conditions.
A calculator .... that's the answer