- Compounds are formed when two or more <u>elements</u> are chemically combined.
- When these elements are <u>chemically</u> combined, a new substance is formed with new chemical and physical <u>properties</u>.
- An element is a <u>pure</u> substance that cannot be separated into simpler substances by <u>physical</u> or chemical means.
- A compound is two or more elements <u>combined</u> chemically to produce a new substance.
- When two or more elements chemically combine, the compound has new properties, different from the chemical and physical properties of the <u>original</u> elements.
<h3>What is a chemical element?</h3>
A chemical element can be defined as a pure substance which comprises atoms that have the same atomic number (number of protons) in its nuclei and as such it is the primary constituent of matter.
Generally, some examples of a chemical element include the following:
- Argon.
- Sodium.
- Carbon.
- Oxygen.
- Hydrogen.
- Phosphorus
- Copper
- Aluminum
- Potassium
- Magnesium
<h3>What is a pure substance?</h3>
A pure substance can be defined as a single sample of matter that cannot be separated into other kinds of matter through the use of any physical or chemical separating technique because it has distinct chemical properties and a definite and constant composition.
Read more on pure substances here: brainly.com/question/2056940
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Alkaline earth metal are the elements present in II group in the periodic table and are known as 'Metals' and have a charge of +2.
Alkaline earth metals - Be , Mg Ca, Sr , Ba, Ra
Halogens are present in VII A group in the periodic table and are 'Non-metals' and have a charge of -1.
Halogens - F, Cl, Br, I, At
When Alkaline earth metal (metals) combine with Halogens (non-metals) the compound formed will be ionic compound and the formula of the compound will be based on the charges of the element.
When we write the formula of the ionic compound the charges of the elements get criss crossed.
For example - Mg (Alkaline earth metal) have a charge of +2 and Cl (Halogen) have a charge of -1 and when they combine to form the formula their charges get criss crossed and we will get 
or 
When an alkaline earth metal, A, reacts with a halogen, X, the formula of the Ionic compound formed should be 
Answer:
The alphabet comprises 21 consonants and 5 vowels
Its electronic confuguration is 2.8.6 so it occupies 3 shells.
