Identifying Characteristics of Atoms Number of
Protons
Number of
Neutrons
Atomic
Number
Mass
Number
Element
(symbol)
B
С
A
20
20
19
F
E
9
D
Using the periodic table, complete the table to describe each atom. Type in your answers.
A
B
С
D

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

Non metal is an element or substance that is not a metal metal is a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivitymetalloid is an element (e.g., germanium or silicon) whose properties are intermediate between those of metals and solid nonmetals. they are electrical semiconductors.