The elements are Helium (2 protons, 2 neutrons, 2 electrons), Chlorine (17 protons, 18 neutrons, 17 electrons), and Calcium (20 protons, 20 neutrons, 20 electrons).
The image you've shared is a table with information about different elements. Here's how you can solve it step by step:
1. Identify each element by its number of protons using the Periodic Table
- The number of protons in an atom is also known as the atomic number, and it determines the identity of an element. For example, an atom with 2 protons is a Helium (He) atom, an atom with 17 protons is a Chlorine (Cl) atom, and an atom with 20 protons is a Calcium (Ca) atom.
2. Determine the number of electrons for a neutral atom (which should equal the number of protons).
- In a neutral atom, the number of electrons equals the number of protons. So, a neutral Helium atom has 2 electrons, a neutral Chlorine atom has 17 electrons, and a neutral Calcium atom has 20 electrons.
3. Use information about isotopes to deduce neutron numbers when necessary.
- The number of neutrons in an atom can vary, creating different isotopes of the same element. The most common isotopes of Helium, Chlorine, and Calcium have 2, 18, and 20 neutrons respectively.
So, the completed table would look like this:
attached below:
