Classification of Elements

What is the primary basis for the arrangement of elements in the modern periodic table?

• Atomic mass

• Number of neutrons

• Atomic number

• Number of electron shells

Which subatomic particle primarily determines the chemical properties of an element?

• Proton

• Neutron

• Electron

• Nucleus

Elements in the same group of the periodic table exhibit similar chemical properties because they have the same:

• Atomic number

• Number of electron shells

• Number of valence electrons

• Atomic mass

How many protons are there in an atom with an atomic number of 15?

• 5

• 10

• 15

• 30

Which of the following describes the general trend of atomic radius as you move from left to right across a period in the periodic table?

• Increases

• Decreases

• Remains constant

• First increases, then decreases

Which of the following describes the general trend of metallic character as you move down a group in the periodic table?

• Increases

• Decreases

• Remains constant

• First decreases, then increases

An element with an atomic number of 11 belongs to which block in the periodic table?

• s-block

• p-block

• d-block

• f-block

The number of electron shells in an atom corresponds to its:

• Group number

• Period number

• Atomic number

• Valency

Which of the following elements is a halogen?

• Sodium (Na)

• Calcium (Ca)

• Chlorine (Cl)

• Neon (Ne)

What is the charge of an electron?

• Positive

• Negative

• Neutral

• Varies depending on the atom