Answer:
a) The ion symbol for an atom with 27 protons and 25 electrons is:
Example: 1. Identify the element based on the number of protons (atomic number). In this case, the atom has 27 protons, so it belongs to the element with atomic number 27, which is cobalt (Co).
2. Determine the charge of the ion based on the difference between the number of protons and electrons. Since the atom has 25 electrons, which is 2 fewer than the number of protons, the ion has a charge of +2.
3. Write the ion symbol by indicating the element symbol followed by the charge in superscript. Therefore, the ion symbol for an atom with 27 protons and 25 electrons is Co²⁺.
b) The ion symbol for an atom with 34 protons and 36 electrons is:
1. Identify the element based on the number of protons (atomic number). In this case, the atom has 34 protons, so it belongs to the element with atomic number 34, which is selenium (Se).
2. Determine the charge of the ion based on the difference between the number of protons and electrons. Since the atom has 36 electrons, which is 2 more than the number of protons, the ion has a charge of -2.
3. Write the ion symbol by indicating the element symbol followed by the charge in superscript. Therefore, the ion symbol for an atom with 34 protons and 36 electrons is Se²⁻.