Answer:
Dalton's atomic theory consisted of several postulates.
Explanation:
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All matter consists of indivisible particles called atoms.
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Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.
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Atoms cannot be created or destroyed.
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Atoms of different elements may combine with each other in a fixed, simple, whole number ratio to form compound atoms.
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Atoms of same element can combine in more than one ratio to form two or more compounds.
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Atoms are the smallest unit of matter that can take part in a chemical reaction.
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Answer: Atomic Particles
Explanation:
toms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
Answer: Mass of gas is 0.001 pounds.
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of gas = ?
Density of gas = 
Volume of gas = 389 ml = 0.389 L (1L=1000ml)
Putting in the values we get:
(1g =0.002 lb)
Thus the mass of gas is 0.001 pounds.
Answer:
Antoine Lavoisier and Johann Wolfang Döbereiner organized the elements based on properties such as how the elements reacts or whether they are solid or liquid.
Explanation:
The periodic table of the elements as we have it today was developed as a result of the work of several notable centuries who lived centuries apart, all of who made notable contributions to development of the modern periodic table in use today.
In 1789, Antoine Lavoisier, a French Chemist provided a definition of elemets which he defined as a substance whose smallest units cannot be broken down into a simpler substance. He further grouped the elements into two as metals and nonmetals.
In 1829, German physicist Johann Wolfang Döbereiner arranged elements in groups of three in increasing order of atomic weight and called them triads. His arrangement owasf elements into triads was based on his observation of similarities in physical and chemical properties of certain elements.
John Newlands, a British Chemist was the first to arrange the elements into a periodic table with increasing order of atomic masses.
In 1869, Russian chemist Dmitri Mendeleev developed a periodic table which provided a framework the modern periodic table. He arranged the elements according to their atomic weight, leaving gaps for elements that were yet to be discovered.
The modern periodic table arranges elements based on increasing atomic number.
Answer:
D
Explanation:
From periodic table : proton number 19 corresponds to K (potassium)
which is very reactive with water
