(5 points) 2. a neutral atom of phosphorus has 15 electrons. explain why the electron configuration below is not the correct configuration for a neutral atom of phosphorus in its ground state. 1s2 2s2 2p6 3s2 3p2 4s1 (5 points) 3. find rubidium, magnesium, and aluminum on the periodic table. fill in the table below based on the locations of these metals on the periodic table. be thorough in filling in the far right column! element symbol group number number of valence electrons general reactivity of the metal with an explanation for this reactivity based on the number of valence electrons rubidium magnesium aluminum

Answer 2 : The given electronic configuration for a neutral atom of phosphorous in its ground state is incorrect.

Explanation :

A neutral atom of phosphorous has 15 electrons.

The given electronic configuration is incorrect.

The reason is, According to Aufbau principle, the electrons will be first filled in the sub-shell having lower orbital energy. As from the given configuration, 3p sub-shell has lower orbital energy than 4s sub-shell. So, the electrons will be filled in 3p sub-shell first. Hence, the ground state electronic configuration of neutral atom of phosphorous is,

Answer 3 :

Element                     Rubidium              Magnesium                Aluminium

Symbol                             Rb                         Mg                              Al

Group number                  1                             2                               13

Number of valence          1                             2                                3

electrons

The order of general reactivity on the basis of number of valence electrons.

Rb > Mg > Al

Reason : The reactivity is determined by the number of electrons present in the outermost shell that means the element which have 1 valence electron will be more reactive because they can easily lose electrons.

increased stability in the completion of fluorine's outer shell.