The valence electrons are determined by the column that the element falls in.
Column 1 has 1 valence electron
Column 2 has 2 valence electrons
Column 13 has 3 valence electrons
Column 15 has 5 valence electrons
column 16 has 6 valence electrons
column 17 has 7 valence electrons
Elements are trying to become stable by filling the outer energy level. Columns 1,2,3 do this by losing 1,2 or 3 electrons and becoming positive ions. +1, +2, +3, respectively
Columns 15, 16, 17 do this by taking those electrons and becoming negative ions. -3, -2, -3. respectively.
Pass the mixture through a screen to allow the salt and pepper to pass through but traps the pebbles. Mix the salt and pepper with water to dissolve the salt and filter it to get the pepper.
AuI3, or Gold Iodide.
Hope this helps! :)
Simply look at the periodic table and fill in what you know based on the table
The number of protons = atomic number
The number of electrons, Which is the same as the atomic number for atoms.
The number of valence electrons that is given by the group that the element is in, the top number of each column in the periodic table.