| Name of Element | Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |

Question

|------------------|----------------|-------------|---------------|---------|----------|-----------|
| Argon | Ar | __ | 18 | __ | __ | __ |

Answer 1

To fill in the missing values for Argon (Ar):

1. Mass Number: The mass number is the sum of protons and neutrons in the nucleus of an atom. For Argon, the most common isotope has 18 protons (its atomic number) and typically has 22 neutrons. Therefore: \[ \text{Mass Number} = \text{Protons} + \text{Neutrons} = 18 + 22 = 40 \]

2. Protons: The atomic number of Argon is 18. Therefore, the number of protons is also 18.

3. Neutrons: Based on the mass number we calculated: \[ \text{Neutrons} = \text{Mass Number} - \text{Protons} = 40 - 18 = 22 \]

4. Electrons: In a neutral atom, the number of electrons is equal to the number of protons, so Argon has 18 electrons.

Now, we can fill in the values:

| Name of Element | Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons | |------------------|----------------|-------------|---------------|---------|----------|-----------| | Argon | Ar | 40 | 18 | 18 | 22 | 18 |