La estructura de los átomos

The video discusses the evolution of the periodic table, highlighting Mendeleev's initial arrangement by atomic mass and Mosley's later adjustment to organize elements by atomic number. This change clarified the natural order of elements, linking atomic structure to chemical behavior. The video explains how electron shells determine element properties and reactivity, with each period corresponding to a filled electron shell. It also covers the trends in reactivity across groups, emphasizing the role of outer electrons. The final arrangement of elements validates Mendeleev's work, showing a true natural order in chemistry.

Who proposed the arrangement of elements by atomic number instead of atomic mass?

• Niels Bohr

• Henry Mosley

• Dmitri Mendeleev

• John Dalton

What defines each element according to the modern periodic table?

• Number of neutrons

• Number of electrons

• Atomic mass

• Number of protons

How many electrons can the second electron shell hold?

• 6

• 4

• 8

• 2

What is the key factor that determines the similarities and reactivity of elements in the same column?

• Number of protons

• Number of outer electrons

• Atomic mass

• Number of neutrons

Which group of elements is known for having only one outer electron, making them highly reactive?

• Group 7

• Group 6

• Group 2

• Group 1