Explanation

The state of matter with the minimum space between particles is a solid. 

In a solid, the particles are tightly packed together with very little space between them,

Resulting in strong intermolecular forces and a definite shape.

Liquids have more space between particles than solids, and gases have the most space with the particles moving freely at high speeds. 

Explanation

The rate of diffusion is fastest in gases, compared to liquids and solids. 

Diffusion is the movement of particles from an area of high concentration to an area of low concentration.

In gases, the particles are very far apart and move with high kinetic energy,

Allowing them to move freely and quickly, resulting in the fastest rate of diffusion.

Liquids have particles closer together than gases, but still more freedom of movement than solids.

Solids have particles tightly packed together with strong intermolecular forces, restricting their movement and making diffusion very slow. 

Explanation

An α-particle is a helium nucleus. 

An alpha particle is composed of two protons and two neutrons,

It is the same composition as a helium nucleus,

Making it essentially a helium nucleus without its electrons

Explanation

Canal rays, also known as anode rays

They are streams of positively charged particles (ions) observed in gas discharge tubes.

Discovered by Eugen Goldstein in 1886,

They travel in the opposite direction of cathode rays (electrons). 

Explanation

Ernest Rutherford showed (1919) that nitrogen under alpha-particle bombardment ejects what appear to be hydrogen nuclei.

By 1920 Ernest Rutherford had accepted the hydrogen nucleus as an elementary particle, naming it proton.

while

Electron was discovered by J. J. Thomson in 1897.

Explanation

Lactose, also known as milk sugar.

It is a disaccharide composed of galactose and glucose molecules.

It is found in milk and other dairy products.

Explanation

• Fluorine is the most electronegative element (3.98 on the Pauling scale).
• 7 valence electrons (2s² 2p⁵); needs one more for a stable noble gas configuration
• Small atomic radius → strong pull on bonding electrons
• High effective nuclear charge

Explanation

Limestone consists of calcium carbonate,

which has the chemical formula CaCO3.

Calcium carbonate is a chemical compound.

It is a common substance found in rocks as the minerals calcite.

Explanation

Potassium is the chemical element.

Symbol: K 

Atomic number: 19

Electron configuration: 4s1

Electrons per shell: 2, 8, 8, 1

Explanation

Portland cement is mainly made from calcium oxide (CaO), which is obtained by heating limestone.

It acts as the binder in concrete.