Question

( 2 )
2. In the modern periodic table, the periods indicate the
value of
(a) atomic number
(b) mass number

(c) principal quantum number
(d) azimuthal quantum number
​

Answer 1

Answer:

atomic number I think .if I help u then plzark me as brainlist

Answer 2

Answer:

(c) principal quantum number

Explanation:

In the modern periodic table, the period indicates the value of principal quantum number for the outermost shell or valence shell..