Explanation

• Ethyl alcohol was prepared by Al-Razi (also known as Rhazes).
• He was a Persian polymath who made significant contributions to chemistry and medicine, including the distillation of alcohol.

Explanation

• Noble gases are stable because their outermost energy level is full, meaning they have eight electrons in their valence shell.
• This full outer energy level gives them a stable electronic configuration, similar to that of the noble gases, and makes them unreactive.

Explanation

• The number of protons and neutrons in an atom are added together to obtain the total number of nucleons.
• It is also known as the mass number.

Explanation

• One atmospheric pressure, also known as standard atmospheric pressure.
• It is defined as 101325 Pascals (Pa).
• This is the pressure exerted by the weight of the atmosphere at sea level.
• It is used as a standard unit of pressure.

Explanation

• The diagram that shows atoms are bonded with the same electronegativity is: A -----:----- B.
• In this representation, the bond is shown with a symmetrical distribution of electrons.
• It suggesting that the atoms have the same or very similar electronegativity.

Explanation

Chlorine can be displaced by fluorine (F).

This is because fluorine is more reactive than chlorine.

As halogen reactivity decreases down the group in the periodic table.

Explanation

In a Daniell cell, the following is used as a cathode:

• Copper (Cu): The copper electrode is reduced and gains electrons to form copper atoms.
• The half-reaction is: Cu2+(aq) + 2e- → Cu(s)

Explanation

The molar mass of sodium chloride (NaCl) is 58.44 g/mol.

To find the mass of 2 moles of NaCl, you can multiply the molar mass by 2: 2 mol × 58.44 g/mol = 116.88 g

Rounded to the nearest gram, this is approximately 117 grams.

Explanation

The elements in group VIIA of the periodic table are called halogens.

This group consists of the following elements:

• Fluorine (F)
• Chlorine (Cl)
• Bromine (Br)
• Iodine (I)
• Astatine (At)
• Tennessine (Ts)

Explanation

• The atomic number 19 corresponds to the element Potassium (K).
• The electron configuration of Potassium is: 1s² 2s² 2p⁶ 3s¹
• Which can be simplified to: 2, 8, 8, 1.