Particles in a gas are far apart compared to a solid or liquid, allowing it not to have a definitive shape or volume. This also means that gases can fill any container and be easily compressed.
Answer:
- <em>He realized that some elements had not been discovered.</em>
Explanation:
Some scientists that tried to arrange the list of elements known before Mendeleev include Antoine Lavoisier, Johann Döbereiner, Alexandre Béguyer de Chancourtois, John Newlands, and Julius Lothar Meyer.
<em>Dimitri Mendeleev</em> was so succesful that he is recognized as the most important in such work.
Mendeleev by writing the properties of the elements on cards elaborated by him, and "playing" trying to order them, realized that, some properties regularly (periodically) repeated.
The elements were sorted in increasing atomic weight (which is not the actual order in the periodic table), but when an element did not meet the pattern discovered, he moved it to a position were its properties fitted.
The amazing creativity of Mendeleev led him to leave blanks for what he thought were places that should be occupied by elements yet undiscovered. More amazing is that he was able to predict the properties of some of those elements.
When years after some of the elements were discovered, the genius of Mendeleev was proven because the "new" elements had the properties predicted by him.
Answer:
All the numbers in a chemical formula are significant, It is because the numbers in a chemical formula denote the number of different atoms present in the particular compound.
For example in H2SO4 there are 2 H 1 S and 4 O. This means 1 H2SO4 has 2 hydrogen 1 sulphur and 4 oxygen.
To figure out the ratios of these compounds, it is important to remember that the charge of these compounds must be <em>
neutral</em>.
So in order to make them neutral, you must have specific ratios:

; This is true because they both have a charge of magnitude of 1.

; We need 3 chlorine atoms because we need to balance out the charge from the 3+ charge of aluminum - therefore since chlorine has a 1- charge, we need 3 atoms.

; The charges of the magnesium (2+) are balanced with the oxygen charge (2-).

; This is correct because if charges are like this, you must find the least common factor in order to know the ratio. The LCF is 6, therefore, for the atom with a 3+ charge, you need 2 of them, and for the atom with a 2- charge, you need 3 of them. This keeps the charge neutral.
Answer:
The correct answer is that it is made of atoms that are covalently bonded together.
Explanation:
Hope this helped Mark BRAINLEST!!!