What does the submicroscopic world of the atom include?
The submicroscopic world of the atom includes exotic particles called quarks and gluons. Like other well-known Greek philosophers of the time, Aristotle agreed with Democritus’ ideas about atoms.
Did Moseley discover that all atoms of an element have the same number of neutrons in their nuclei?
Moseley discovered that all atoms of an element have the same number of neutrons in their nuclei. Atoms with the same number of protons but different numbers of electrons are called isotopes.
What important contribution did Lavoisier make to Dalton’s atomic theory of matter?
What important contribution did Lavoisier make to Dalton’s atomic theory of matter? Lavoisier helped the atomic theory of matter, by stating that matter is not destroyed or created, it just changes form. Located inside the nucleus, has a positive charge, and 1 amu.
What would Proust say about the composition of all carbon dioxide molecules?
What would Proust say about the composition of all CO2 molecules? He would say that all CO2 molecules contain exactly the same percentage of carbon and exactly the same percent of oxygen by mass.
What is the significance of drawing the 90% contour of orbitals?
Explain the significance of drawing the 90% contour of orbitals. It encloses 90% of the electron density, with the likeliness of finding an electron being the same for all points on the surface and within.
Is it true that there are about 5000 elements which combine to form the vast number of different substances in the world around us?
Chem 9 weeks test
| Question | Answer |
|---|---|
| there are about 5000 elements, which combine to form the vast number of different substances in the world among us | false 100 |
| it is possible to actually see atoms w=using a scanning tunneling microscope | true |
What were the 3 missing elements in the periodic table?
Gallium, germanium, and scandium were all unknown in 1871, but Mendeleev left spaces for each and predicted their atomic masses and other chemical properties. Within 15 years, the “missing” elements were discovered, conforming to the basic characteristics Mendeleev had recorded.
What did Henry Moseley discover about the periodic table?
In 1913 he used self-built equipment to prove that every element’s identity is uniquely determined by the number of protons it has. His discovery revealed the true basis of the periodic table and enabled Moseley to predict confidently the existence of four new chemical elements, all of which were found.
How did Lavoisier contribute to the atom?
A later breakthrough in the discovery of the atomic model came through the work of French chemist Antoine Lavoisier who through a series of experiments found that the total mass of products and reactants in a chemical reactions is always the same. This led to the theory of the law of conservation of mass.
What would Proust say?
“Let us be grateful to the people who make us happy; they are the charming gardeners who make our souls blossom.” “The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.” “Always try to keep a patch of sky above your life.”