Question

element:

protons:

neutrons:

electrons:

mass number:

Explanation:

Step1: Identify the element

The symbol \( F \) represents fluorine.

Step2: Determine the number of protons

The atomic number (subscript) is \( 9 \). In a neutral atom, the number of protons equals the atomic number. So, the number of protons is \( 9 \).

Step3: Calculate the number of neutrons

The mass number (superscript) is \( 19 \). The formula for the number of neutrons is \( \text{Neutrons}=\text{Mass number}-\text{Protons} \). So, \( 19 - 9=10 \).

Step4: Find the number of electrons

The ion is \( F^{-1} \), which means it has gained one electron. A neutral fluorine atom has \( 9 \) electrons. So, \( 9 + 1=10 \).

Step5: Identify the mass number

The mass number (superscript) is \( 19 \).

Answer:

element: fluorine

protons: \( 9 \)

neutrons: \( 10 \)

electrons: \( 10 \)

mass number: \( 19 \)