Answer:
Gasoline
Explanation:
Pure Substance: are those having same type of atoms or molecules.
Compound: one or more atoms of the element combine to form a compound.
Mixture: is combination of one or more substances mix together.
Homogeneous Mixture: are those which are not distinguish by naked eye but can be separated into its components by physical means
Heterogeneous mixture: are those which can be distinguishing by naked eye and can be separated into its components by physical means.
So keeping in mind the above definitions
Table salt:
The chemical formula of table salt is NaCl and it a pure compound not mixture.
Gasoline:
Gasoline is mixture of hydrocarbon, It contains small hydrocarbons ranging from 4 Carbon to 12 Carbon per molecule. it is a homogeneous mixture.
Aluminum:
Aluminum is a pure substance that is made up of same kind of atoms. so it is an element and not mixture. Its symbol is Al
Carbon dioxide:
Carbon dioxide is a pure compound and its chemical formula is CO₂ and not a mixture.
So, the write option is Gasoline.
The mass number of the atom is 21, the atomic number is 9, and the element is Fluorine. There are 9 protons, 9 electrons, 12 neutrons, and the elemental symbol is F.
<h3>Properties of an atom</h3>
For every atom:
- Protons and neutrons are located in the nucleus and the addition of both equals the mass number of atoms.
- Electrons are located outside the nucleus, in orbitals.
- Neutral atoms have the same number of electrons and protons
In the diagram:
Number of electrons = 9
Number of protons = 9
Number of neutrons = 12
Mass number = 12 + 9
= 21
Atomic number = number of protons
= 9
Element with atomic number 9 = Fluorine
Symbol of the element = F
More on atoms can be found here: brainly.com/question/1566330
#SPJ1
1- Movement
2- Respiration
3- Growth
