Final answer:
Atoms become positively charged ions, or cations, when they lose electrons. This is because they have more protons than electrons after the loss, resulting in a positive charge.
Step-by-step explanation:
When atoms lose electrons, they become ions with a positive charge. These positively charged ions are known as cations. A neutral atom can lose some electrons from its valence shell, which leads to an excess of protons relative to electrons, resulting in a positive electrical charge. For instance, a neutral sodium atom (Na) that loses one electron becomes a sodium cation (Na+), and a neutral calcium atom (Ca) losing two electrons becomes a calcium cation (Ca2+). The atomic charge becomes positive since the number of protons – which remains unchanged – now exceeds the number of electrons.
An important concept to remember is that atomic charge can be calculated as the number of protons minus the number of electrons. Ions are reactive and their formation, known as ionization, occurs due to various processes such as exposure to radiation or electron transfer during chemical reactions.