Answer:
Explanation:
The atomic number tells you how many protons are in an element. Each element has a different number of protons, so a specific number of protons will also help you easily identify that particular element. For example, if you are given that an element has an atomic number of 1, you would know the element is hydrogen because other elements have different amounts of protons and thus different atomic numbers.
Answer:
1.3 meters
Explanation: use newton third law equation.
By determining the period that the element is in. For example, Calcium is in period 2 therefore its valence electron is located on energy level 2.