C2.1 MODERN PERIODIC TABLE

Question 1

what is changed from Mendeleev

Answer 1

now arranged in order of atomic number

Question 2

Mendeleev arrange in atomic weight, why

Answer 2

because protons weren’t discovered

Question 3

what is wrong with ordering in atomic weights

Answer 3

some elements can appear wrong due to the presence of isotopes

Question 4

modern periodic table has what

Answer 4

noble gasses