G8 , General Revision T1

...... layer in atmosphere that is suitable for flying planes

• troposphere

• stratosphere

• thermosphere

..................... discover the main energy levels in the atom

• Bohr

• Mendeleev

• Mosely

............... cause blindness

• Arsenic

• iron

• mercury

................. is used in preserving of eye cornea

• liquefied sodium

• liquefied nitrogen

• silicon

............. replaces the wood organic material , part by part of an old tree

• plastic

• iron

• minerals

ozone is found in ..... layer

• troposphere

• mesosphere

• stratosphere

the density of ice is ..... the density of water

• less than

• more than

• equal to

the atomic number of an element that exists in group 7A and period 2 is ......

• 12

• 7

• 9

the atomic size decreases in the same group as atomic number increases

• true

• false

the air moves horizontally in the lower part of startosphere

• true

• false