| Atomic symbol | Atomic Number | Protons | Neutrons | Electrons | Atomic mass |

Question

|---------------|---------------|---------|----------|-----------|-------------|
| __ | __ | 89 | __ | __ | 225 |

Answer 1

The atomic symbol for the element with atomic number 89 is "Ac," which stands for Actinium.

To fill in the missing values in the table:

• Atomic Symbol: Ac
• Atomic Number: 89
• Protons: 89 (the number of protons is equal to the atomic number)
• Neutrons: The number of neutrons can be calculated by subtracting the atomic number from the atomic mass (rounded to the nearest whole number).
  • Neutrons = Atomic mass - Atomic number = 225 - 89 = 136
• Electrons: In a neutral atom, the number of electrons equals the number of protons, so electrons = 89.
• Atomic Mass: 225 (given)

Here is the completed table:

| Atomic symbol | Atomic Number | Protons | Neutrons | Electrons | Atomic mass | |---------------|---------------|---------|----------|-----------|-------------| | Ac | 89 | 89 | 136 | 89 | 225 |