Determine the number of valence electrons for magnesium through the use of this table. mg =

Answer : The number of valance electrons for magnesium are 2.

Explanation :

The given element is magnesium (Mg). The element magnesium belongs to group 2 and period 3.

The atomic number of magnesium is 12 and the atomic mass is 24.

The number of electrons present in magnesium are 12.

So, the electronic configuration of magnesium will be,

From the electronic configuration we conclude that, the outermost shell of magnesium is '3s' and the number of electrons present in '3s' is 2. And we know that the number of electrons present in outermost shell is known as valance electrons.

Hence, the number of valance electrons for magnesium are 2.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.