Unit 2 - Materials and their Properties - grade 9

Atoms must have an equal number of electrons and _______

• protons

• neutrons

• molecules

• ions

The atomic mass is the total of the number protons and ________.

• electrons

• neutrons

• ions

• molecules

The atomic number is same as the number of _______ in an atom.

• Electrons

• Neutrons

• Protons

• Ions

Elements belonging to the same group in the periodic table have the same number of _______ in their outmost of electron shells.

• neutrons

• ions

• protons

• electrons

Ionic bonds are formed only between ______________

• metals and nonmentals

• metals

• nonmetals

Covalent bonds are formed only between __________

• metals and nonmetals

• nonmetals

• metals

The ionic bond is the electrostatic force of attraction between a positively charged metal ion and a negatively charged non-metal ion.

• True

• False

A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms of same or different nonmetal elements.

• True

• False

_____________ are the elements that have the tendency of gaining electrons in order to gain stability, that is, they exhibit electronegativity.

• Non-metals

• Metals

• Metalloids

___________ are the elements that have the tendency of losing electrons in order to gain stability, that is, they exhibit electro-positivity.

• Non-metals

• metals

• Metalloids