Which represents a Ca atom with two positive electrical charges (Ca2+)? (a)
(b)
(c)

Key Concepts

Atomic Structure

An atom consists of a nucleus containing protons and neutrons, surrounded by electrons in various energy levels. The number of protons defines the element, while the arrangement of electrons determines its chemical properties. For calcium (Ca), the atomic number is 20, indicating it has 20 protons and, in its neutral state, 20 electrons.

Ionic Charge

Ionic charge refers to the electrical charge an atom acquires when it loses or gains electrons. A Ca atom can lose two electrons to achieve a stable electron configuration, resulting in a Ca2+ ion, which has a positive charge due to the excess of protons over electrons. This process is essential in understanding how elements interact in chemical reactions.

Chemical Symbols and Notation

Chemical symbols are shorthand representations of elements, with each symbol consisting of one or two letters. The notation for ions includes the element's symbol followed by its charge, such as Ca2+ for a calcium ion with a +2 charge. This notation is crucial for identifying ions in chemical equations and understanding their roles in reactions.