Which two elements have the same number of valence electrons?
a. barium
b. silicon
c. neon
d. carbon?

we know that

In the periodic table, each column is called a group. The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons.

see the attached figure

therefore

the answer is

Silicon and Carbon have the same number of valence

Carbon and silicon have same number of valance electrons which is 4 electrons.

Valance electrons are the electrons present in the outermost shell of the atom. The number of valance electrons define the valancy of the atom.

Now, Barium is a 2nd group element. So, it has two valance electrons.

Silicon is a 16th group element and it has 4 valance electrons as does the carbon. This is because they both stay in the same group in the periodic table.

Neon is a noble gas which has 8 valance electrons and stays in the 18th group.

Therefore, carbon and silicon have same number of valance electrons which is 4 electrons.

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