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Phys. Science chap.3
Physical Science chapter 3
Question | Answer |
---|---|
what is an atom? | it is the smallest piece of an element that still has the properties of the element. |
what the nucleus? | central region of an atom. It contains 2 types of particles |
proton | has +1 charge. contributes 1 amu to the mass of an atom |
amu | is the atomic mass unit |
neutron | has no charge(neutral) contrubutes 1 amu to mass of atom |
electron | has -1 charge. does NOT contribute to the mass of an atom. |
How did we figure out structure of an atom | people first came up with ides, these ideas were called models, like a model airplane, it is a small scale pic. or diagram to help us understand something |
**Remember that not all models end up correct. that is why we change our ideas and came up with an idea about how electons move in atoms. We have changed the model since then** | ** |
Energy Level | electrons exisit at certain distances fom the nucleus. electrons at farther distances from the nucleus have higher energy then closer ones. Many energy levels can hold 8 electrons. |
Orbital | a region in space around a necleus where there is a high probablility of finding electrons. each energy level has orbitals of various shapes. (also known as a particular shape in space) |
what is a valence??? | 1 it is the outer energy level of an atom |
2 electrons in this energy level are called valence electrons | 3 valence electrons are involved in making bonds with other atoms. valence electrons are responsible for chenical reactions. |
Periodic Law | when we put elements in order of increasing atomic number, similarities in their properties occur in regular patterns. (EX.- melting points go up and down...etc. at regular intervals) |
Period | a horizontal row in the periodic table |
Group | a vertical column in the periodic table |