Explanation

Group 1 (alkali metals) and Group 2 (alkaline earth metals) are the longest (tallest) in the periodic table because they contain the most elements vertically across periods — from period 1 down to period 7.

Explanation

Beta rays (or beta particles) are high-energy electrons, which inherently carry a negative charge.

This is why they are deflected toward the positive plate in an electric field. 

Explanation

Lithium is the lightest metal.

Density of 0.534 g/cm³.

It is an alkali metal,

The third element on the periodic table,

It is soft enough to be cut with a knife.

Uses: Due to its low density and high reactivity, it's used in aircraft and, famously, in the production of batteries for electric vehicles and consumer electronics. 

Explanation

- Discovered by: Henry Cavendish  

- Year: 1766  

Symbol: H

Atomic mass: 1.00784 u

Atomic number: 1

Named by: Antoine Lavoisier (1783)

Explanation

John Dalton is considered the 'Father of Modern Atomic Theory.

He raised the atomic theory that acted as an explanation of the following two laws.

Law of conservation of mass – According to the law, mass can neither be destroyed nor created in any chemical reaction.

Explanation

Iron is the metal with the highest percentage in stainless steel

Iron (Fe):

The foundational element, providing the main structure, usually 60-75%.

Chromium (Cr):

Essential for rust resistance, forming a protective passive layer, typically 10.5% to 30%.

Nickel (Ni):

Added to enhance ductility, strength, and corrosion resistance, especially in austenitic grades (like 304 stainless steel, which has 8% nickel).

Carbon (C):

A small amount (under 1.2%) is present, influencing hardness and other properties. 

Explanation

Nitrous oxide is commonly called laughing gas.

It is used to induce anesthesia during surgeries.

It helps patients remain unconscious or pain-free during medical procedures.

Explanation

Alfred Nobel was a chemist from Sweden. 

Dynamite was invented by Alfred Nobel in the 1860s.

He is also the founder of the Nobel Prize

He also invented Nitro-glycerine in 1875.

Alfred Nobel  Born: October 21, 1833, Stockholm, Sweden

Alfred Nobel  Died: on December 10, 1896, in Sanremo, Italy

Alfred Nobel Full name: Alfred Bernhard Nobel

Additional Information

The first Noble Prize was awarded on 10th December 1901

The first Noble Prize was awarded in Stockholm, Sweden.

Explanation

Melting of ice changes only the state from solid to liquid.

No new substance is formed, so it's a physical and reversible change.

Explanation

Temporary hardness of water is caused by dissolved bicarbonates of calcium and magnesium.

It can be removed by boiling, which decomposes Ca(HCO₃)₂ into insoluble carbonate.