Answer:
Explanation:
Covalent bond:
It is formed by the sharing of electron pair between bonded atoms.
The atom with larger electronegativity attract the electron pair more towards itself and becomes partial negative while the other atom becomes partial positive.
Non polar covalent bond:
It is the bond where both bonded atoms share the pair of electron equally.
For example:
Hydrogen gas (H₂) is non polar covalent compound because the electronegativity of both bonded atoms are same. No poles are created that's why this is non polar covalent compound.
Polar covalent bond:
It is the bond where both bonded atoms share the pair of electron unequally.
For example:
In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive and bond is polar.
It would take 4 years to reach earth
Answer: protons and neutrons.
The nucleus is made up of 3 subatomic particles that are protons,neutrons and electrons.
General notation of an element is 
where, X is the Element, A is the Atomic Mass and Z is the Atomic Number
If we know the number of protons we can easily find out the atomic number of any element because Atomic Number = Number of protons in an element.
And in addition if we know the number of neutrons we can easily find out the atomic mass of an element because
Atomic Mass = (Number of protons) + (Number of neutrons)
If we get to know the atomic number and atomic mass, we can easily tell what element is it by looking from the periodic table.
Answer:
HNO₂
Explanation:
An acid is a proton donor; a base is a proton acceptor.
Thus, NO₂⁻ is the base, because it accepts a proton from the water.
H₂O is the acid, because it donates a proton to the nitrite ion.
The conjugate base is what's left after the acid has given up its proton.
The conjugate acid is what's formed when the base has accepted a proton.
NO₂⁻/HNO₂ make one conjugate acid/base pair, and H₂O/OH⁻ are the other conjugate acid/base pair.
NO₂⁻ + H₂O ⇌ HNO₂ + OH⁻
base acid conj. conj.
acid base
