Question

give me the answer as soon as possible​

Answer 1

Answer:

Explanation:

a) In the modern periodic table, atomic number was used as the fundamental basis.  This removed various  anomalies of Mendeleev's periodic table.  Position of cobalt and nickel were also justified.

b) If you move directly down a column, the number of energy levels or shells increases.

As you go down the horizontal rows, the energy levels increase.

pls mrk as brainliest