Video Transcript
What is the complete chemical symbol for the atom that contains three protons, three electrons, and four neutrons?
The complete chemical symbol of an atom can be expressed using nuclide notation. In this notation, the letter E represents the chemical symbol of the element as found on the periodic table. The letter 𝐴 represents the mass number. The mass number of an atom is equal to the sum of the number of protons and the number of neutrons in the nucleus. The letter 𝑍 represents the atomic number of the element. The atomic number is equal to the number of protons in an atom.
Now that we can recognize each component of nuclide notation, we can begin to complete the chemical symbol for the atom in the question. We are told that this atom contains three protons. Since the atomic number is equal to the number of protons, we can replace the symbol 𝑍 with the number three. This number also helps us to identify the chemical symbol. When we look at a cell on the periodic table, the number written above the chemical symbol is the atomic number. We know that the atomic number of this atom is three. So this atom must be an atom of lithium. Therefore, we can replace the letter E in the nuclide notation with the chemical symbol of lithium, Li.
To determine the mass number, we simply need to add together the number of protons and the number of neutrons in this atom. From the question, we know that the number of protons is three and the number of neutrons is four. Therefore, the mass number of this atom is seven. So the complete chemical symbol for an atom that contains three protons, three electrons, and four neutrons is seven over three Li.
