Chemistry Chapter 5

• The smallest particle of the naturally occurring isotopes of an element
• Simple model of the atom
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• A negatively charged particle within an atom
• Electrons are NOT in the nucleus
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• A particle that is smaller than the atom
• i.e.- Nuetrons, Electrons, and Protons

• In chemistry, the positively charged center of an atom
• The nucleus contains neutrons and protons
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• A positively changed particle that is part of every atomic nucleus
• The blue dots in the diagram below are protons
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• An uncharged particle that is part of almost every atomic nucleus
• The red dots in teh diagram below are neutrons
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• Areas of space surronding the nucleus of an atom that electrons occupy
• The row the element is in tells you how many energy levels it has with electrons in it
• The energy levels on the diagram below are the thin black lines around the nucleus
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• The number of protons in the nucleus of an atom
• i.e.- Oxygen has an atomic number of 8

• The sum of the number of protons and the number of neutrons in the nucleus of an atom
• i.e.-Oxygen has a mass number of 16

• One of two or more forms of an element that have the same number of protons but a different number of neutrons
• i.e.- hydrogen-1 and hydrogen-2 are different isotopes of hydrogen because they have different numbers of neutrons.
• In the diagran below there is a hydrogen-1 atom, a hydrogen-2 isotope, and a hydrogen-3 isotope
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• Used to show the arragnement of subatomic particles for an element
• Protons and neutrons- placed in a centre circle
• Electrons- placed in surrounding cirlces
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• The average mass of the naturally occurring isotopes of an element
• i.e.- Oxygen has an atomic mass of 16

A system for organizing the elements into columns and rows, so that elements with similar properties are in the same column

• Typically, an element that is hard, shiny, malleable, and is a good conductor of heat and electricity
• Metals are found on the left side of the perodic table and areblue on the diagram below
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• Typically, an element that is not shiny, malleable, and is a poor conductor of heat and electricity
• Non-metals are found on the right side of the periodic table and are yellow on the diagram below
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• An element that shares some properties with metals and some properties with non-metals
• Metalloids are green on the diagram below and are found in a bold stair case on most periodic tables
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• A horizontal row of elements in the periodic table
• The periods are numbered from 1-7 from top to bottom as shown below
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• A vertical column of elements in the periodic table
• The groups are labelled 1-18 from left to right as shown below
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• A group of elements that all have low melting points, are highly reactive, and are soft enough to be cut with a knife. They have 1 valence electron (Group 1 in the periodic table)
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• A group of elements that are all very reactive (but less that group 1 and 17), capable of burning in air, and produce bright coloured flames. They have 2 valence electrons (Group 2 in the periodic table)
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• A group of elements that are all highly reactive, extremely corrosive, and the bottom of the group has a high melting point. They have 7 valence electrons (Group 17 in the periodic table)
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• A group of elements that are all colourless, odorless, gases at room temperature which are non-reactive. They have a full set of valance electrons
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• An electron in the outermost occupied energy level of an atom
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