Explanation

1. Sodium (Na)
2. Hydrogen (H)
3. Carbon (C)
4. Oxygen (O)

Explanation

Ferrum is the Latin name for iron, which is why its chemical symbol is Fe.

It is a transition metal used widely in construction.

It is essential in the human body for forming hemoglobin.

Explanation

Boron is a metalloid, showing properties between metals and non-metals.

Aluminum is a metal.

Phosphorus is a non-metal.

Explanation

The d subshell has 5 orbitals, each can hold 2 electrons, so total 10 electrons.

This is standard in electron configuration rules in chemistry.

Explanation

Molar mass of CO₂ = 12 (C) + 16×2 (O) = 44 g/mol

Number of moles = Mass / Molar mass = 60 / 44 ≈ 1.364 mol

Explanation

Fe = 56, N = 14 × 2 = 28, O = 16 × 6 = 96 → Total = 56 + 28 + 96 = 180 amu

This is the correct formula mass for Iron (II) Nitrate, Fe(NO₃)₂.

Explanation

Carbon has 4 electrons in its outer shell.

It forms 4 covalent bonds, making it tetravalent (valency = 4).

Explanation

Sand and gravel are commonly used in filtration to remove impurities and suspended particles from water.

They provide a physical barrier and are effective in both slow and rapid sand filtration processes.

Explanation

Coagulation helps neutralize the charges on particles so they can stick together.

Flocculation follows, where these particles clump into larger flocs for easy removal—both are key in water purification.

Explanation

The era from 600 A.D to 1600 A.D is known as the period of Alchemists in Muslim history, especially in the Islamic Golden Age.

During this time, Muslim scholars like Jabir bin Hayyan advanced early chemical and alchemical knowledge.