The statement that is NOT a part
of John Dalton's atomic theory Electrons move in specific orbits around the
nucleus of an atom. The statements ‘All elements are composed of atoms that
cannot be divided’, ‘All atoms of the same element are exactly alike and have
the same mass’ and ‘Every compound is composed of atoms of different elements,
combined in a specific ratio’ are not his theory.
<span>Matter is composed of particles that have kinetic energy. Particles with greater kinetic energy tend form liquids or gases due to increased rates of activity of the particles. Particles with lower energy tend to form solids. So, a solid forms when the average energy of a substance's particles decreases.</span>
Answer:
C. They don't react with other elements to form compounds
Explanation:
The elements in Group 18 of the periodic table are called "inert", or noble gases.
These elements have their valence shell (the outermost shell of the atom) full of electrons, so they do not gain/give off electrons, and therefore, they do not react with other elements, so they do not form compounds.
In fact, normally the elements try to gain/give off electrons in order to fullfill their outermost shell (the valence shell). For instance, an atom that has 1 electron only in its valence shell, try to "give away" this electron in order to have its outermost shell completed. On the other hand, an atom which has 7 electrons in its valence shell tries to "gain" one electron in order to fullfill the valence shell.
Noble gases, instead, have already 8 electrons in their valence shell, so their valence shell is already completed, therefore they do not react with other elements, and therefore they are called "inert".
Answer:
HBr + H₂SO₄ → SO₂ + Br₂ + H₂O An oxidizing agent is a substance that itself becomes reduced and oxidizes the other chemical species in the reaction mixture. A reducing agent is similar, except that it becomes oxidized and reduces the other substance. In the reaction, the valency of bromine changes from -1 to 0, so it is oxidized
Explanation:
B
A definite chemical composition means that all occurrences of that mineral have a chemical composition that varies within a specific limited range and the atoms that make up the mineral must occur in specific ratios.
