20.
Atomic number is equivalent to its protons and electrons. :)
Answer:
The halogens are extremely reactive, whilst the noble gases are mainly inert.
Only some noble gases tend to form compounds, such as xenon and krypton. However, some like helium, almost have no compounds at all.
Noble gases also have octet rule shells, which causes the little reactivity associated with them.
To form bonds with noble gases, a lot of energy is required to form those bonds.
Halogens, on the other hand, are extremely reactive. Compounds like chlorine and fluorine must be stored carefully, as they will oxidise anything that they can find, just to get one extra electron to get an octet configuration.
Hope this helps :)
The general formula for alkenes is CnH2n, the formula with hydrogen count double the carbon count should be the correct formula for alkene and that is d. C3H6.
What are alkenes?
Alkenes, commonly known as olefins, are organic unsaturated hydrocarbons that have one or more carbon-carbon double bonds in their chemical structure and are composed of carbon and hydrogen atoms.
Alkenes are unsaturated hydrocarbons with a double bond between the carbon atoms. Carbon atoms are connected by at least one double bond. The general formula for alkenes is C n H 2n. Olefin is frequently substituted with alkenes. The word "olefin" comes from the Greek phrase "olefin gas," which denotes the production of oil.
<u>Since, their general formula is CnH2n, the formula with hydrogen count double the carbon count should be the correct formula for alkene and that is d. C3H6.</u>
To learn more about alkenes from the given link below,
brainly.com/question/27179090
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Answer:
Volume of water at this temperature is 27.2 mL
Explanation:
We know that 
Here density of water is 0.992 g/mL
Here mass of water is 27.0 g
So 
= 
= 27.2 mL
A volumetric flask is used to contain a predetermined volume of substance and only measures that volume, for example 250 ml.
Conical flasks can be used to measure the volume of substances but the accuracy they provide is usually up to 10ml. Conical flasks are used in titrations, reactions where the liquid may boil, and reactions which involve stirring.
Pippettes are of two types, volumetric and graduated. Pippettes are used where high accuracy is required and volumetric pippettes come in as little as 1 ml. Pippettes are usually used in titrations.
Graduated cylinders come in a wide variety of sizes and their accuracy can be down to as much as 1 ml. They are used to contain liquids.
