Chemistry 7-8-9 unit

WHAT BOND IS POTASSIUM CHLORIDE (KCl)

• covalent bond

• hydrogen bond

• ionic bond

• metallic bond

Which one is covalent bond?

• 
• 
• 
• 

...... - the element with the strongest nonmetallic properties

• francium

• boron

• copper

• fluorine

Which one is exothermic reaction?

• Burning of wood
• Photosynthesis
• Melting ice
• 

Some elements have properties of metals and nonmetals more at the same time.

Such elements are called .....

• solids

• amphoteric elements

• metalloids

• acidic oxids

Which elements are liquid at room temperature

• Carbon and sulfur
• Oxygen and nitrogen
• Mercury and bromine
• Sodium and potassium

The vertical columns are called.....

• pillars
• periods

• rows
• groups

The most stable elements are noble gases.Why?

• Noble gases have a high reactivity with other elements.
• Noble gases have a high melting point.
• Noble gases have a full outer electron shell.
• Noble gases have a high atomic mass.

Supersaturated solution is....

• Contains less of the dissolved material than could be dissolved by the solvent under normal circumstances
• Contains more of the dissolved material than could be dissolved by the solvent under normal circumstances
• Contains an equal amount of the dissolved material as could be dissolved by the solvent under normal circumstances
• Contains only a small amount of the dissolved material

metals have a tendency to

• donate electrons

• receive electrons