Problem 13 - Chemistry: The Central Science

Question

Write the Lewis symbol for atoms of each of the following elements: (a) \(\mathrm{Al}\), (b) \(\mathrm{Br}\), (c) \(\mathrm{Ar}\), (d) \(\mathrm{Sr}\).

Step-by-Step Solution

Answer

The Lewis symbols for the given elements are: (a) Al: \[\chemfig{Al(-[:0,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)}\] (b) Br: \[\chemfig{Br(-[:0,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)(-[:225,.5]-[,0.5]H)(-[:270,.5]-[,0.5]H)(-[:315,.5]-[,0.5]H)}\] (c) Ar: \[\chemfig{Ar(-[:0,.5]-[,0.5]H)(-[:45,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:135,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)(-[:225,.5]-[,0.5]H)(-[:270,.5]-[,0.5]H)(-[:315,.5]-[,0.5]H)}\] (d) Sr: \[\chemfig{Sr(-[:0,.5]-[,0.5]H)(-[:45,.5]-[,0.5]H)}\]

Step 1: Determine the number of valence electrons

Aluminium is in group 13 of the periodic table, which means it has 3 valence electrons.

Step 2: Write the Lewis symbol

To write the Lewis symbol, place the chemical symbol in the center and arrange the three valence electrons around it, with two on one side and one on the other side. Lewis symbol for Aluminium (Al) is: \[ \chemfig{Al(-[:0,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)} \] (b) Bromine (Br)

Step 1: Determine the number of valence electrons

Bromine is in group 17 of the periodic table, which means it has 7 valence electrons.

Step 2: Write the Lewis symbol

To write the Lewis symbol, place the chemical symbol in the center and arrange the seven valence electrons around it, with four placed on one side and three on the other side. Lewis symbol for Bromine (Br) is: \[ \chemfig{Br(-[:0,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)(-[:225,.5]-[,0.5]H)(-[:270,.5]-[,0.5]H)(-[:315,.5]-[,0.5]H)} \] (c) Argon (Ar)

Step 1: Determine the number of valence electrons

Argon is in group 18 of the periodic table, which means it has 8 valence electrons.

Step 2: Write the Lewis symbol

To write the Lewis symbol, place the chemical symbol in the center and arrange the eight valence electrons around it. As Argon is a noble gas, it has a full octet and doesn't usually form bonds with other elements. Lewis symbol for Argon (Ar) is: \[ \chemfig{Ar(-[:0,.5]-[,0.5]H)(-[:45,.5]-[,0.5]H)(-[:90,.5]-[,0.5]H)(-[:135,.5]-[,0.5]H)(-[:180,.5]-[,0.5]H)(-[:225,.5]-[,0.5]H)(-[:270,.5]-[,0.5]H)(-[:315,.5]-[,0.5]H)} \] (d) Strontium (Sr)

Step 1: Determine the number of valence electrons

Strontium is in group 2 of the periodic table, which means it has 2 valence electrons.

Step 2: Write the Lewis symbol

To write the Lewis symbol, place the chemical symbol in the center and arrange the two valence electrons on one side. Lewis symbol for Strontium (Sr) is: \[ \chemfig{Sr(-[:0,.5]-[,0.5]H)(-[:45,.5]-[,0.5]H)} \]