To determine which atom has a charge of -1, we'll need to understand the concept of atomic charge. The charge of an atom is calculated by subtracting the number of protons from the number of electrons:
[tex]\[ \text{Charge} = \text{Number of electrons} - \text{Number of protons} \][/tex]
Let's calculate the charge for each atom given in the table:
- Atom 1:
[tex]\[
\text{Protons} = 9, \text{Electrons} = 9
\][/tex]
[tex]\[
\text{Charge} = 9 - 9 = 0
\][/tex]
- Atom 2:
[tex]\[
\text{Protons} = 9, \text{Electrons} = 8
\][/tex]
[tex]\[
\text{Charge} = 8 - 9 = -1
\][/tex]
- Atom 3:
[tex]\[
\text{Protons} = 9, \text{Electrons} = 10
\][/tex]
[tex]\[
\text{Charge} = 10 - 9 = 1
\][/tex]
- Atom 4:
[tex]\[
\text{Protons} = 9, \text{Electrons} = 9
\][/tex]
[tex]\[
\text{Charge} = 9 - 9 = 0
\][/tex]
From the calculations above, we see that Atom 2 has a charge of -1. Therefore, the atom with a charge of -1 is:
2