science Grade 8

When an atom gains or loses electrons, the charged particle that results is called ( molecule ) .

• False /ion

• False / polar

• True

Which type of substance would best dissolve in a solvent that was made of nonvolatile molecules

• A water based slovent

• AAn Ionic compound

• A solute made of polar molecules

• A solute made of no polar molecules

Which can change the solubility of a solid in a liquid

• Crushing the solute

• Stirring the solute

• IIncreasing The pressure

Which ions are present in the greatest amount in a solution whith pH of 8.5 ?

• HHydrogen Ions

• Hydronium ions

• Hydroxide ions

In carbon dioxide, each oxygen atom shares four electrons whith the carbon atom . What is this type of bond called ?

• TTriple Covalent

• Double covalent

• Polar covalent

• IIonic

In general , nonmetals are

• Good conductors of electricity

• Malleable and ductile

• GGases At room temperature

Chemical equations are balanced by changing subscript

• TTrue

• False

According to the law of conservation of mass , three atoms of calcium can react to produce six atoms of calcium

• True

• False

In an atom , an electron that is close to the nucleus is on the highest energy level

• FFalse

• TTrue

How many dots are shown in the electron dot diagram for calcium group 2 , element number 20 ?

• 1

• 2

• 20