How Many Valence Electrons Does Calcium Have?
Calcium is a chemical element with the symbol Ca and atomic number 20. It is the fifth most abundant element by mass in the Earth’s crust, and the third most abundant metal. Calcium is a soft, silvery-white alkaline earth metal. It is highly reactive and forms compounds with almost all other elements.
How many valence electrons does calcium have?
The answer is two. A valence electron is an electron that is found in the outermost shell of an atom. The number of valence electrons determines the chemical properties of an element.
Calcium has an atomic number of 20. This means that it has 20 protons in its nucleus. It also has 20 electrons, since an atom is electrically neutral. The 20 electrons are arranged in four shells, with two electrons in the first shell, eight electrons in the second shell, eight electrons in the third shell, and two electrons in the fourth shell.
The two electrons in the fourth shell are the valence electrons. They are the electrons that are most likely to be involved in chemical reactions.
Related questions
- How can I find the number of valence electrons for an element?
One way to find the number of valence electrons for an element is to look at the periodic table. Elements in the same group on the periodic table have the same number of valence electrons. For example, all elements in group 2, including calcium, have two valence electrons.
Another way to find the number of valence electrons for an element is to write the electron configuration for the element. The electron configuration tells you how many electrons are in each shell of an atom. For example, the electron configuration for calcium is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² In this electron configuration, the s and p orbitals are the valence shells. There are two electrons in the 4s orbital, so calcium has two valence electrons.
What is the significance of the number of valence electrons?
The number of valence electrons determines the chemical properties of an element. Elements with the same number of valence electrons tend to react in similar ways. For example, all elements in group 2 are alkaline earth metals. They are all soft, silvery-white metals that react easily with water to form hydroxides.
In the case of calcium, its two valence electrons make it a reactive metal. Calcium can easily lose these two electrons to form a +2 ion. This ion is very stable and is often found in compounds of calcium.