Answer:
The number of neutrons present in one atom of isotope of Silicon of mass 28 amu is<u> 14 neutrons</u>
Explanation:
Symbol of Si isotope

<u>Number of Neutron = Mass number - Atomic Number</u>
Mass number = Total number of protons and neutrons present in the nucleus of the atom.For Si = 28 amu
Atomic Number = Total number of Protons present in the nucleus.
Si = 14
Number of neutron = 24 - 14
= 14
Chemical change can be determined when a substance change it's state of composition and is irreversible. Five evidences that chemical change has occured are, color change, formation of a precipitate, formation of gas, odor change, temperature change. Examples of chemical change are, combustion reactions, rusting iron, precipitate of AgCl.
Matter is discontinuous, and it is made of tiny particles called atoms
Explanation:
Matter is not a continuous structure, but it consists of tiny particles called atoms.
An atom consists of three types of particles:
- Proton: the proton is in the nucleus of the atom. it has a positive electric charge of
(also called fundamental charge). Its mass is
.
- Neutron: the neutron is also in the nucleus of the atom, but it has no electric charge. Its mass is similar to the mass of the proton (slightly heavier). Neutrons and protons are held together in the nucleus through the strong nuclear force.
- Electron: electrons are found in a "cloud" outside the nucleus. Electron has negative electric charge equal to
. Its mass is much approximately 1800 times smaller than that of the proton, so it is considered as negligible.
Learn more about atoms and matter:
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Answer:
Centimeters or milimeters.
Explanation:
The answer depends on the size of the box.
<em>The metric system </em><u><em>base</em></u><em> unit for length is the meter</em>. <em>Centimeters</em> and <em>milimeters</em> are thus also part of the metric system.
If the box is a "regular-sized" box that we use to put stuff in (books, presents, etc), then centimeters would be the most appropiate.
If we're talking about those tiny boxes that are printed on paper (for example in some notebooks) then milimeters would be the most appropiate.
2Ca+O2<span>➡2CaO
You need to balance it by adding a 2 as the coefficient on the Ca, then put 2 on the products side
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