Answer:
Hydrogen has 0 neutrons.
Explanation:
You can find the # of neutrons by subtracting the Atomic Mass from the Atomic number. Hydrogen is a special case in which the atom has no neutrons.
Answer:
every real machine must be less than 100 because of the force that overcome friction
Lithosphere, asthenosfhere , lower mantle
Explanation:
Compound: a substance that is made up of more than 1 type of atom bonded together Example: H2O
Mixture: combination of two or more elements or compounds not chemicaly bonded together. example: Sugar and salt in one container
elements pure substance of an atom. Example: hydrogen
Answer: C.) polyatomic anion
Explanation: Cations are the ions which carry a positive charge and anions are the ions which carry a negative charge. Monoatomic ions are those which consists atoms of similar elements and polyatomic ions are those which consists of atoms of different elements.
For example : 
is a monoatomic cation.
is an monoatomic anion.
is a polyatomic cation.
is a polyatomic anion as it consists of atoms of phosphorous and oxygen and bears a negative charge.
