Answer:
Explanation:
To answer this question successfully, we need to remember that atoms are neutral species, since the number of protons, the positively charged particles, is equal to the number of electrons, the negatively charged particles. That said, we may firstly find an atom which has 3 electrons (and, as a result, 3 protons, as it should be neutral).
The number of protons is equal to the atomic number of an element. We firstly may have an atom with 3 protons and 3 electrons (atomic number of 3, this is Li).
Similarly, we may take the atomic number of 4, beryllium, and remove 1 electron from it. Upon removing an electron, it would become beryllium cation, 
.
We may use the same logic going forward and taking the atomic number of 5. This is boron. In this case, we need to remove 2 electrons to have a total of 3 electrons. Removal of 2 electrons would yield a +2-charged cation: 
.
Period are going left to right across the periodic table
Groups are going up to down on the periodic table
1) To find the change in enthalpy, determine the difference between the potential energy of the products and the potential energy of the reactants. (on this diagram, C-A) To find the activation energy, find the difference between the potential energy of the reactants and the "peak" of the curve (on this diagram, B-A). For this diagram, both the enthalpy and activation energy are positive.
2) If the reaction was exothermic, enthalpy would be negative, and the potential energy of the reactants would be greater than the potential energy of the products.
Answer:
The correct answer is option c.
Explanation:
Alkanes with higher molecular mass has higher boiling point.
Thisis because when the molar mass of the alkanes increases the the surface area increases with which van der Waals forces between the molecules of alkane also increase which increases the association of the molecules of with each other which results in increase in boiling point is observed.
The increasing order of the molar mass of the given alkanes;
So out of ethane, pentane and heptane . Heptane has highest molecular mass with higher boiling point value. Where as ethane have the lowest value of boiling point.
In gamma decay, no change in proton number occurs, so the atom does not become a different element
