Questions

The halogens make up group 17 in the periodic table.

They are five elements:

Chlorine (Cl)

Fluorine (F)

Bromine (B)

Iodine (I)

Astatine (At).

But astatine is not purely halogen as it is radioactive.

The name given to the bond between water molecules is a hydrogen bond. These bonds occur between the slightly negative oxygen of one water molecule and the slightly positive hydrogen of another water molecule. Hydrogen bonding gives water special physical properties.

The differences in electronegativity between hydrogen and oxygen lead to an unequal sharing of electrons. Electronegativity measures how strongly an atom attracts electrons. Oxygen, with its higher electronegativity, pulls on the shared electrons more, giving the oxygen atom a partial net negative charge. The shared electrons spend less time with the hydrogen atoms; therefore, the hydrogen regions of water have partial positive charges.

Plants make their own food through the process of photosynthesis. Plants are self-sufficient. Green plants have the ability to prepare their own food and this is the reason why they are called autotrophs.

They make their own food through the process of photosynthesis using light energy to make sugars from carbon dioxide (C02) and water (H20). The chlorophyll which is present in the leaves is the main reason for the production of food in the plants and it is the reason for the greenery of the leaves too.

Electrons are stripped from water in the light reactions of photosynthesis. Light provides the energy to excite electrons.

ATP and NADPH are both products of the light reactions and are used to power the Calvin cycle.

J. J. Thomson discovered electrons in the year 1897.

Ernest Rutherford discovered protons in 1911.

James Chadwick discovered neutrons.

Al Aziziyah, the hottest place on earth is located in Libya, in North Africa. On 13 September 1922, a high temperature of 58.0 °C was recorded in Al Aziziyah.

This is considered the highest temperature ever measured on Earth.