Final answer:
The columns with elements that can achieve a full valence shell by losing one or two electrons are Columns 1A and 2A, which include alkali metals and alkaline earth metals respectively. Option A is correct.
Step-by-step explanation:
The columns that contain elements with atoms that have only one or two electrons in their valence shell, which can achieve a full valence shell by losing these electrons, are Columns 1A and 2A.
Elements in Column 1A (also known as Group 1 or the alkali metals) have a single valence electron that they can lose to achieve a noble gas configuration. Similarly, elements in Column 2A (also known as Group 2 or the alkaline earth metals) have two valence electrons that they can lose to achieve a full valence shell.
Column 1A includes elements such as hydrogen (H), lithium (Li), sodium (Na), which have one electron in their outermost shells and can donate this electron to become positively charged ions.
In contrast, Column 2A includes elements such as beryllium (Be) and magnesium (Mg), which have two electrons in their outermost shells and can also donate these to become positively charged ions. The answer to the student's question is option A. Columns 1A and 2A.