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Unit 1A
Atoms and Their Parts 8th Grade
Term | Definition |
---|---|
one atom | The smallest unit of an element that has all the properties of that element. |
nucleus | The tiny, very dense positively charged region in the center of an atom. It is made of protons and neutrons. |
electron cloud | All of the area inside an atom but outside the nucleus. It is where electrons are found. |
electrical charge | A form of charge, designated negative, positive, or neutral. It is found on the subatomic particles. |
proton | A positively charged subatomic particle of the nucleus of an atom. It contributes to the mass of the atom. |
neutron | A subatomic particle of the nucleus of an atom. It has no charge. It contributes to the mass of an atom. |
electron | A negatively charged subatomic particle of the electron cloud. It forms chemical bonds with other atoms. |
subatomic particles | Particles that are smaller than the atom. |
atomic mass | The mass of an atom, approximately equal to the number of protons and neutrons in the atom. Always round this number. |
scientific notation | Numbers written in terms of a decimal number between one (1.0) and ten (10.0) multiplied by a power of ten. Used for very large and very small numbers. |
atom | Smallest unit of an element, made of protons, electrons, and neutrons. |
cell | Smallest unit of life; still much larger than an atom. |