A substance is composed of only one kind of Adam and can't be separated into simpler substances are converted into it another substance by chemical processes

Element

Explanation:

An element is substance that is composed of only one kind of atom and can not be separated into simpler substances or converted into another substance by chemical processes.

Chemical elements are found in the periodic table. Examples of chemical elements include; sodium potassium, phosphorus, hydrogen etc.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

5.6⋅10−^19  j

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