Periodic classification of elements

In the modern periodic table elements are arranged by:

• atomic mass
• atomic number
• valence electrons
• number of isotopes

_______________ developed the first periodic table and arranged the elements in order of increasing atomic mass.

• Stevie Wonder
• Sasha Vujacic
• Dmitri Mendeleev
• James Mosely

Vertical columns of elements (these are also known as a "family") - they also have the same number of valence electrons and are known as ________________.

• groups

• periods

• quadrants

• rows

Why were there blank spaces left in Mendeleev's periodic table?                                              

• He didn't know what to put there.
•  Undiscovered elements not yet known.
• Multiple elements could have fit
• He forgot to add the elements in.

Used the law of triads to make a list of elements

• Mendeleev
• Dobereiner
• Mosely

_______________ developed the first periodic table and arranged the elements in order of increasing atomic mass.

• Stevie Wonder
• Sasha Vujacic
• Dmitri Mendeleev
• James Mosely

Which property did Mendeleev use to order his periodic table?

• Shielding effect
• Eletronegitivity
• Atomic Weight
• Metallic Character

first to organize the elements by atomic mass; noticed patterns in every 8th element; law of octaves; left no gaps for future discovery; law of octaves did not work for larger elements

• Dobereiner

• Mendeleev

• Seaborg

• Newlands

How many elements were discovered during Mendeleev's time?                                           

• 63
• 56
• 101
• 34

Which statement is not a difference between Mendeleev's table and the modern periodic table?

• there are no transition elements Mendeleev's table.
• Elements are arranged according to atomic no. not atomic mass.
• no gaps in the modern periodic table.
• much more than 60 elements in the modern periodic table.