grade 7(the matter)

Which of these substances contains the essential elements for plant growth?

• H₃PO₄

• KNO₃

• NH₄K₂PO₄

• NH₄NO₃

The number of electrons in the outer most energy level ₆C is .............. electrons.

• 2

• 4

• 6

• 8

The mass of a proton equals ................

• 1g

• 1kg

• 1u

• 1mg

Both methane and nitric acid molecules contain ........... atoms.

• Nitrogen

• Hydrogen

• Oxygen

• Chlorine

The most active halogen is ..........

• Cesium

• Fluorine

• Sodium

• Oxygen

How many metal atoms are found in one molecule of Egyptian blue dye ?

• 2

• 11

• 15

• 26

All the following are physical properties of a piece of calcium carbonate, except ...........

• is solid

• doesn't dissolve in water

• is white in color

• Produces gas bubbles with vinegar

The elements of d-block are called ...........

• Transition elements

• Inert gases

• Alkaline earth metals

• Alkali metals

If the last energy level of a halogen atom, is the level L , It's atomic number is .........

• 7

• 9

• 17

• 19

The properties of the element whose atomic number is 2 are similar to the properties of the element whose atomic number is ............

• 10

• 12

• 19

• 20