The Building Blocks of the Universe?
The atom - a nanoscopic constituent of matter - has, for a long time been thought to be the most fundamental component of matter. Nowadays, chemists know that atoms are made of protons, neutrons and electrons.
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Relative Mass - The mass of a sub-atomic particle in comparison to each other: an electron is 2000 times smaller than a proton.
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Protons and electrons have charges which are either positive or negative. Theses charges interact with each other in ways described by the electrostatic force. This force causes oppositely charged particles to attract and same-charged particles to repel. This means the electrons in an atom are attracted to the protons which is how they stay 'in orbit'. This would also cause protons in the nucleus to repel each other but the charge-less neutrons keep the protons together.
Elements
An atom has a neutral charge (charge = 0) because it has an equal number of protons to electrons.
The number of protons an atom has is its atomic number/proton number and this determines which element it is.
An element is an atom with a specific number of protons or a substance with atoms of only one atomic number. Examples of elements include oxygen, hydrogen, gold, silver, potassium, sodium, carbon etc.
Isotopes
An isotope is an atom with which is the same element as another (has the same number of protons) but has a different mass (a different number of neutrons).
The Relative atomic mass of an element is its average mass calculated by the equation below. In the below equation, we have used A(x) to describe the percentage of all isotopes of a substance that isotope x is. (if this is 90%, 90% of all of the substance has this isotope).
The elipses (...) indicates a continuation: (A(IsotopeC) etc) depending on how many different isotopes there are.
$$ Relative Atomic Mass = \frac { (A(IsotopeA) * Mass(IsotopeA)) + (A(IsotopeB) * Mass(IsotopeB)) +...}{ Total Percentage } $$
Electrons
Electrons tend to be the most important part of an atom in chemistry as they determine many things about reactions between and properties of substances. Electrons are structured within atoms in shells (energy levels). The first shell contains up to 2 electrons and the following two shells each contain up to 8 more electrons. The electron configuration is how the electrons fill out each shell from inside out.
Elements
An atom has a neutral charge (charge = 0) because it has an equal number of protons to electrons.
The number of protons an atom has is its atomic number/proton number and this determines which element it is.
An element is an atom with a specific number of protons or a substance with atoms of only one atomic number. Examples of elements include oxygen, hydrogen, gold, silver, potassium, sodium, carbon etc.
Isotopes
An isotope is an atom with which is the same element as another (has the same number of protons) but has a different mass (a different number of neutrons).
The Relative atomic mass of an element is its average mass calculated by the equation below. In the below equation, we have used A(x) to describe the percentage of all isotopes of a substance that isotope x is. (if this is 90%, 90% of all of the substance has this isotope).
The elipses (...) indicates a continuation: (A(IsotopeC) etc) depending on how many different isotopes there are.
$$ Relative Atomic Mass = \frac { (A(IsotopeA) * Mass(IsotopeA)) + (A(IsotopeB) * Mass(IsotopeB)) +...}{ Total Percentage } $$
Electrons
Electrons tend to be the most important part of an atom in chemistry as they determine many things about reactions between and properties of substances. Electrons are structured within atoms in shells (energy levels). The first shell contains up to 2 electrons and the following two shells each contain up to 8 more electrons. The electron configuration is how the electrons fill out each shell from inside out.
