The correct pair of best conductors of heat are

• Alluminium and Silver

• Copper and Silver

• Silver and Zinc

• Zinc and Magnesium

Tags

NGSS.HS-PS3-4

Lead and Mercury are

• Best conductors of heat

• Bad conductors of heat

• Poor conductors of heat

• Bad conductors of electricity

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

Elements do not react with oxygen even at high temperature are

• Gold and Silver

• Magnesium and Alluminium

• Sodium and Potassium

• Copper and Zinc

Zn, Fe, Al and Mg. When we arrange these elements in the ascending order of their

reactivity series we get

• Mg < Al < Zn < Fe

• Al < Mg < Fe < Zn

• Zn < Al < Mg < Fe

• Fe < Zn < Al < Mg

Hydrogen gas is not liberated when a metal reacts with HNO₃. This is because

HNO₃ is a

• Weak oxidizing agent

• Strong oxidizing agent

• Weak reducing agent

• Strong reducing agent

Alloys are the

• Heterogenous mixture of metals and non-metals

• Heterogenous mixture of two or more metals

• Homogenous mixture of metals and non-metals

• Homogenous mixture of two or more non-metals

Identify the correct group of soft metals from the following

• Sodium, Alluminium and Copper

• Sodium, Potassium and Lithium

• Copper, Manganese and Magnesium

• Zinc, Barium and Lithium

Observe the given information with respect to some elements and choose the correct name of the elements

Elements A B C D

Electrons K 2 2 2 2

L 8 8 6 8

M 1 8 0 4

N 0 1 0 0

• A is Silicon, B is Sodium, C is Potassium

  and D is Oxygen

• A is Potassium, B is Oxygen, C is Sodium

  and D is Silicon

• A is Oxygen, B is Silicon, C is Potassium and

  D is Sodium

• A is Sodium, B is Potassium, C is Oxygen and D is Silicon

Tags

NGSS.MS-PS1-1

NaCl and CuSO₄ compounds have high melting and boiling points. This is because

• These are easily soluble in water and makes aqueous solutions

• A considerable amount of energy is required to break the strong inter-ionic bond

• They form positive and negative ions by the process of ionization

• Their ions move freely and conduct electricity

The strong force of attraction between the positive and negative ions of ionic

compounds shows their

• Hardness

• Solubility

• Conduction of electricity

• Conduction of heat