An atom has electronic configuration 2, 8, 7.
To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.) N(7) F(9) P(15) Ar(18)

Explanation

To determine which element is chemically similar to the atom with the electronic configuration 2, 8, 7, we can follow these steps:

### Step 1: Identify the Element
The electronic configuration 2, 8, 7 corresponds to an atom with 17 electrons. This means the atomic number of the element is 17. The element with atomic number 17 is Chlorine (Cl).

### Step 2: Determine the Valence Electrons
In the given configuration (2, 8, 7), the last shell has 7 electrons. This indicates that the element needs 1 more electron to complete its octet (to reach a stable configuration of 8 electrons in the outer shell).

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