Answer:
1) Potassium's number of protons is 19
Symbol is K
Mass number is 39.1 u
2) Number 79 on periodic table is Gold
Symbol is Au,
Mass number is 196.97
3) Metals and non-metals
4) Gases
Iodine
Bromine
Fluorine, chlorine
Explanation:
The modern periodic table is the arrangement of atoms in an increasing atomic number.
The Russian chemist, Dmitri Mendeleev arraigned the elements as they appear in the modern periodic table.
It has 18 groups and 7 periods.
These groups belong to the specific classification of the elements.
The periods referred to as the horizontal rows on the periodic table have given much importance than the vertical columns for the actinides and lanthanides.
It is easy to identify the characteristics of the elements present in the modern periodic table.