Positive ions are called and negative ions are called

When the dominant trait or allele completely masks the recessive allele

Explanation:

Mendelian or complete dominance is a relationship of genes in which one allele of a gene pair that codes for a trait expresses itself over the other allele of the gene pair. The allele of the gene pair that expresses itself over the other is the dominant trait or allele, which completely mask the expression of the other allele called the recessive allele or trait.

In the pea plant experiment conducted by Mendel, complete dominance can be seen. For example, for seed color of pea plant, allele for yellow seed color was dominant over allele for green seed color.