Explanation

Explanation

• The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom.
• Consider the table below, which shows data from the first six elements of the periodic table.
• Consider the element helium.
• Its atomic number is 2, so it has two protons in its nucleus.

Explanation

Smelting uses heat and a chemical-reducing agent to decompose the ore,

driving off other elements as gases or slag

and leaving the metal base behind.

Smelting is a method used in the extraction of metals that involves heating the metal oxide produced from roasting with a reducing agent, such as carbon, to obtain pure metal.

ND-21-5-2023

Explanation

• Silver bromide is useful in photography. whilst silver bromide is exposed to light it undergoes photochemical decomposition.
• The silver ions found in silver bromide are decreased to silver metallic which remains as an opaque photo at the photographic film.
• Silver bromide is a light sensitive salt and has been utilized in photography to coat a gel protected movie as silver halides which, after the film has been exposed are ‘evolved’ and render a poor photo of the precise scene fascinated by a digital camera.

Explanation

Rubies are scientifically known as corundum, a rock-forming mineral and crystalline form of aluminium oxide which is two aluminium atoms and three oxygen atoms (Al2O3) in a close packed hexagonal structure.

Corundum typically contains traces of iron, titanium, vanadium and/or chromium.

Explanation

The electricity we use in our homes is called Alternating Current/ Mains supply.

Alternating current is used in most electricity distribution systems for several reasons, but the most important one is the ease with which it can be transformed from one voltage to another

Explanation

• polonium  is not a radioactive element
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• It is found in the form of an elemental state having allotropes with colors black, red and grey.
• Thus it is also a non-radioactive element.
• Polonium is a group of 16 elements with atomic number 84 and an atomic mass of 204.
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• The common 4 radioactive elements are Uranium, Radium, Polonium, Thorium, etc.
  

Explanation

Sulphur is a non-metal element.

It does not exhibit the characteristics of metals, such as conductivity, malleability, and ductility.

Instead, it is brittle and non-conductive.

Explanation

 At a safe distance park in a hazardous chemical incident

Explanation

Sand is cheaper than Iron, Iron is cheaper than Gold,Gold is cheaper than diamond and diamond is cheaper than platinum