Atomic Structure

The video explains the evolution of the periodic table, highlighting Mendeleev's initial arrangement by atomic mass and Mosley's later adjustment to order elements by atomic number. This change clarified the fixed nature of elements and their properties. The video also discusses electron shells and their role in defining periods and groups, explaining why elements in the same group have similar properties. The periodic table's structure is shown to reflect atomic structure and chemical behavior, validating Mendeleev's vision.

What was the key change proposed by Henry Mosley to the periodic table?

• Classifying elements by density

• Arranging elements by atomic number

• Arranging elements by atomic mass

• Grouping elements by color

How does the atomic structure explain the periodicity of elements?

• By the weight of the elements

• By the number of neutrons in the nucleus

• By the arrangement of electrons in shells

• By the color of the elements

What determines the similarities and reactivity of elements in the same group?

• The density of the element

• The number of protons

• The atomic mass

• The number of outer electrons

Which group of elements is known for having one outer shell electron?

• Group 7 elements

• Group 2 elements

• Group 1 elements

• Group 6 elements

What trend is observed as you move down a group in the periodic table?

• Atoms become more colorful

• Atoms become lighter

• Atoms become larger

• Atoms become smaller