Question

use your knowledge of the periodic table and match the atom to the number and location of their valence electrons.
selenium, se
gallium, ga
rubidium, rb
sodium, na
:: 4 valence electrons on the 3rd energy level
:: 3 valence electrons on the 4th energy level
:: 1 valence electron on the 3rd energy level
:: 3 valence electrons on the 6th energy level
:: 6 valence electrons on the 4th energy level
:: 1 valence electron on the 5th energy level

Explanation:

Step1: Determine valence electrons and energy level for Sodium (Na)

Sodium (Na) has an atomic number of 11. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{1}\). The valence electron is in the 3rd energy level and there is 1 valence electron. So, Na matches “1 valence electron on the 3rd Energy Level”.

Step2: Determine valence electrons and energy level for Gallium (Ga)

Gallium (Ga) has an atomic number of 31. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{1}\). The valence electrons in the outermost relevant level (considering main - group valence electrons for this simple match) for the purpose of this basic valence - electron count (using the group number for main - group elements, Ga is in group 13). The valence electrons in the 4th energy level: there are 3 valence electrons (from \(4s^{2}4p^{1}\)). So, Ga matches “3 valence electrons on the 4th Energy Level”.

Step3: Determine valence electrons and energy level for Selenium (Se)

Selenium (Se) has an atomic number of 34. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{4}\). Using the group number (Se is in group 16), the number of valence electrons in the 4th energy level is 6 (from \(4s^{2}4p^{4}\)). So, Se matches “6 valence electrons on the 4th Energy Level”.

Step4: Determine valence electrons and energy level for Rubidium (Rb)

Rubidium (Rb) has an atomic number of 37. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}5s^{1}\). The valence electron is in the 5th energy level and there is 1 valence electron. So, Rb matches “1 valence electron on the 5th Energy Level”.

Answer:

Sodium (Na): 1 valence electron on the 3rd Energy Level; Gallium (Ga): 3 valence electrons on the 4th Energy Level; Selenium (Se): 6 valence electrons on the 4th Energy Level; Rubidium (Rb): 1 valence electron on the 5th Energy Level.