Question

number of protons equal the number of electrons.
sum of the protons and neutrons.
protons. this number will identify the atom.
same number but different number of neutrons.
the first one is completed as an example.
identity
determine the atomic number and identify the atom by using the periodic table.
li
lithium
isotope
symbol - mass
li - 7
f - 19
isotope notation
mass#px
73li

Explanation:

Step1: Find atomic number of fluorine

Look up fluorine (F) in periodic table. Atomic number of F is 9.

Step2: Write identity

Identity is Fluorine.

Step3: Write isotope notation

Isotope notation for F - 19 is $^{19}_{9}F$.

Answer:

Identity: Fluorine
Isotope: F - 19
Isotope Notation: $^{19}_{9}F$