<span>I think the correct
answer is 109.5 degrees. The bond angle of a chlorite ion or ClO2- ion is 109.5
and has a bent shape. This is because of two groups of bonding electrons and
two lone pairs of electrons. Another example of a molecule that has a bent
molecular geometry is water. It results from its tetrahedral electron pair
shape.</span>
Answer: Protons
WHY?
Changing electrons will only result in the same element having different charges and hence, changing it's chemical properties.
Changing neutrons will not change an element but it will result in an isotope forming instead. (Isotopes are elements of the same type with different neutron numbers.)
However, changing the proton number would immediately change the nucleus composition, resulting in a change in element with a negative charge as there are more electrons than protons. This results in a expansion in valance electrons's distance from the nucleus. This results in a change in chemical properties of the element.
Therefore, a change in Protons is the answer.
The equilibrium vapor pressure of a liquid is the pressure exerted by a vapor on the liquid at a given temperature. It is measured in atm.
Molarity is defined as the moles of solute per liter of solution. 
. Where M is molarity, n is the number of moles and V is the volume. First we must find the molar mass of 
which is 109.98 g/mol
Then we find the molarity using above equation
