development of the periodic table

Question 1

why do all groups of elements react in similar ways?

Answer 1

they have the same number of electrons in their outer energy level

Question 2

what are triads?

Answer 2

elements that have similar chemical properties in groups of threes

Question 3

how did Newland order element son periodic table?

Answer 3

in order of increasing atomic weight

Question 4

what did Mendeleev create?

Answer 4

first modern periodic table

Question 5

how did Mendeleev order elements?

Answer 5

increasing atomic weight but changed the order where he found the elements fitted better in other group with similar properties. he also left group where he thoughts elements were missing. elements missing were proved correct

Question 6

how is modern periodic table organised?

Answer 6

increasing atomic number

Question 7

what is the problem of ordering elements in order of atomic weight?

Answer 7

be in wrong order due to isotopes