Answer:
28
Explanation:
it states that the atom is neutral, meaning the number of electrons and protons are the same. so if there are 13 electrons, there are 13 protons. And the mass number is neutrons plus protons. So 13+15 is 28
In descending order from top:
E
F
D
A
C
B
All you really need to do is remember the symbols of each, and you’ve got it.
Kr= krypton
K= potassium
C=carbon
En= neon
Si= silicon
Au= gold
Ni= nitrogen
Br= berillium
Mg=magnesium
Mn= mangenese
Al: aluminum
In viewing a chemical equation,we <span>determine the ratios that relate reactants and products </span>from the coefficients of the reactants and products .