Final answer:
An atom may lose an electron to become more stable, often forming a cation. This is common in metals with loosely held outer electrons. The tendency to lose electrons is influenced by an atom's position in the periodic table and its nuclear charge.
Step-by-step explanation:
An atom can lose an electron due to several factors. One common reason is the involvement in chemical reactions where it may transfer an electron to another atom, becoming a cation. This transformation makes the atom more stable, as it achieves a filled or empty outermost energy level.
Metals, such as those in groups 1 and 2 of the periodic table, often lose electrons easily due to their single or paired s orbital electrons. Furthermore, increased nuclear charge, resulting from a higher atomic number as you move across the periodic table, can influence an atom's ability to lose electrons. The stronger nuclear attraction in atoms with more protons can make it more difficult for them to lose electrons. However, when an atom does lose an electron, despite an increased atomic number, it forms a cation due to the imbalance of protons and electrons.