How does the electron configuration of elements within the same group compare? (a.) they all have their valence electrons in the same energy level. ( b) they all have their valence electrons in the same type of subshell. (c) they all have their valence electrons in a p suborbital. ( d) they all have their valence electrons in the 3rd energy level.

( B) They all have their valence electrons in the same type of subshell.

Explanation:

With each period, a new shell is added to the atom.

Further, the groups are classified based on the type of subshell the last electron enters and number of valence electrons.

For all elements of same group, the last electron enters the same type of subshell.

Say, for group 1, last electron enters s orbital and they have 1 valence elctron.

for group 17, last electron enters p orbital and they have 7 valence electrons.

(A) and (D) are wrong because, energy level of the valence electrons is determined by the principle quantum number n and l and not by the type of subshell(only l) they enter.

(C) if the valence electron enters p orbital, then the elements will be placed in the p- block.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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