For groups 13 through 18, the number of valence electrons is equal to the group number

a. minus 10
b. minus the period number
c. plus 1
d. plus the period number ​

a. minus 10

Explanation:

An element in group 13 = Boron ,valence electrons = 3 , therefore, valence electrons in group 13 = group no. -10

An element in group 18 = Neon, valence electrons = 8 , therefore, valence electrons in group 18 = group no. - 10

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

solute : a solute is a substance that is dissolved in another substance is known as a solvent. it is mixed with a special mixture know as homogeneous mixture.

solvent: a solvent is a substance that dissolved a solute, which results in a solution is known as solvent.