Which of the following statements are true about whether atoms tend to gain or lose electrons?
A. Atoms with four valence electrons will always lose electrons.
B. Atoms with eight valence electrons easily lose electrons.
C. Atoms with five, six, or seven valence electrons will gain
electrons.
D. Atoms with one, two, or three valence electrons will lose
electrons.

The true statements are;

C and D

Explanation:

The tendency of an atom to gain or lose electrons in a chemical reaction are given by its electronegativity and electropositivity respectively

Electronegativity is a measure of an atom's capacity to attract electrons from neighboring particles, with atoms that are more likely to gain an electron, being described as having a higher electronegativity

Electronegativity increases across the period with increasing number of valence electrons, therefore, elements with five, six, or seven electrons, which are located on the far right of the periodic table are said to have higher electronegativity and therefore more likely to gain electrons in a chemical reaction

Electropositivity is the quantification or measure of an element to donate or give electrons and become positively charged ions in a chemical reaction

The fewer the number of valence electrons an element has, the more likely the element will undergo a reaction by donating the valence electrons to a more electronegative atom and become positively charged

Electropositivity decreases across the period and therefore, elements with one, two, or three valence electrons which are located in groups I, II, and III, are more likely to lose electrons in a chemical reaction

wavelength variability is the right one