Which classification method involves grouping elements into sets of three based on similar properties?

Dobereiner’s Triads

True or False: Mendeleev's periodic table arranged elements by increasing atomic number.

False. Mendeleev's periodic table arranged elements by increasing atomic mass.

Fill-in-the-blank: According to ______, the properties of every eighth element are similar to the first when arranged by atomic mass.

Newland’s Law of Octaves

Which group of elements is known for having a stable electronic configuration and being largely unreactive?

Noble gases (Group 18)

What significant property did Henry Moseley discover that redefined the basis for the periodic table?

Atomic number

True or False: The modern periodic law states that the properties of elements are a periodic function of their atomic mass.

False. The modern periodic law states that the properties of elements are a periodic function of their atomic number.

Fill-in-the-blank: Elements in Group 1 are known as ______ due to their high reactivity.

Alkali metals

Which set of elements was predicted by Mendeleev to exist based on gaps in his periodic table?

Eka-aluminium and eka-silicon

Multiple Choice: Which of the following groups contains elements that typically have two valence electrons? A) Group 1 B) Group 2 C) Group 17 D) Group 18

B) Group 2

What trend occurs in atomic size as you move down a group in the periodic table?

Atomic size increases.

Fill-in-the-blank: The elements with atomic numbers 57 to 71 are known as ______.

Lanthanides

True or False: Transition elements are characterized by having incomplete outermost shells.

True.

What is the primary reason for classifying elements in the periodic table?

To study elements in an organized way.

Multiple Choice: Which of the following is a characteristic of halogens? A) They are all gases B) They have seven valence electrons C) They are non-metals D) B and C only

D) B and C only

Fill-in-the-blank: Mendeleev's periodic table contained vertical columns called ______.

Groups

What do the elements in the same group of the periodic table have in common?

They have the same number of valence electrons.

True or False: Isotopes of an element have different chemical properties.

False. Isotopes have similar chemical properties but different atomic masses.