An atom has 34 protons and 36 electrons. What element is it (and what is the ion’s charge)?

• A. Selenium, ${Se}^2$$-$
• B. Bromine, ${Br}^2$$-$
• C. Selenium, neutral $Se$
• D. Krypton, ${Kr}^2$$-$

Answer: (A)

Verified step by step guidance

1. Identify the element by the number of protons, since the atomic number equals the number of protons. Here, the atom has 34 protons, so find the element with atomic number 34 on the periodic table.
2. Determine the charge of the ion by comparing the number of protons and electrons. The charge is calculated as: \(\text{Charge} = \text{Number of protons} - \text{Number of electrons}\).
3. Calculate the charge using the given numbers: 34 protons and 36 electrons. This will tell you if the ion is positive, negative, or neutral.
4. Write the element symbol with the appropriate charge as a superscript. For example, if the charge is -2, the ion is written as \(\mathrm{Se}^{2-}\) for selenium with a 2- charge.
5. Confirm the element name and the ion charge based on your calculations and periodic table information to finalize the answer.