Select the period 4 alkaline earth metal on the periodic table below.
The Correct Answer and Explanation is:
The period 4 alkaline earth metal on the periodic table is Calcium (Ca).
Explanation:
The alkaline earth metals belong to Group 2 of the periodic table. These elements are characterized by having two electrons in their outermost electron shell, which they tend to lose easily to form +2 cations. The alkaline earth metals are located in the second column of the periodic table, and they include:
- Beryllium (Be) – Period 2
- Magnesium (Mg) – Period 3
- Calcium (Ca) – Period 4
- Strontium (Sr) – Period 5
- Barium (Ba) – Period 6
- Radium (Ra) – Period 7
In Period 4, the alkaline earth metal is Calcium (Ca). Calcium has the atomic number 20, meaning it has 20 protons in its nucleus and, in its neutral state, 20 electrons. Its electron configuration is [Ar] 4s², showing that it has two electrons in the 4s orbital, which is characteristic of alkaline earth metals. Calcium is a soft, gray metal that reacts with water to form calcium hydroxide (Ca(OH)₂) and hydrogen gas. It is essential for biological processes, including bone and teeth formation in humans and other organisms, due to its role in the structure of calcium phosphate.
In summary, Calcium (Ca) is the period 4 alkaline earth metal, and it exhibits all the typical characteristics of this group, such as the tendency to lose two electrons and form +2 ions
