Ch 3: Elements & Periodic Table Study Guide – Flashcards
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1- atom
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- basic particle from which all elements are made.
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1 - nucleus
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- very small center core of an atom, containing protons and neutrons. (plural - nuclei)
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1 - atom measurement
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- too small to be measured in everyday units of mass (grams or kilograms) - atomic mass units (amu) used.
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1 - element
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- pure substance that cannot be broken down into other substances by chemical or physical means - identified by the number of protons in the nucleus of its atoms.
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1 - atomic number
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- the number of protons in the nucleus of an element.
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1 - isotopes
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- atoms with the same number of protons and a different number of neutrons.
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1 - mass number
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- the sum of protons and neutrons in the nucleus of an atom.
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1. - model
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- a diagram, a mental picture, a mathematical statement, or an object that helps explain ideas about the natural world
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1 - protons
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small, positively charged particle in the nucleus
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1- neutrons
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- have no charge, are neutral.
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1 - electrons
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- move rapidly around the nucleus, have a negative electric charge, indicated by -
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2 - atomic mass
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- the average mass of all the isotopes of an element
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2 - periodic table
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- chart of the elements showing the repeating pattern of their properties.
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2 - chemical symbol
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- one or two letter representation of an element.
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2 - period
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- a horizontal row of elements in the periodic table.
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2 - group
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- elements in the same vertical column of the periodic table; also called family.
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3 - metal
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- class of elements characterized by physical properties including shininess, malleability, ductility, & conductivity.
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3 - malleable
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- material that can be pounded into shapes.
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3 - ductile
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- material that can be pulled out into a long wire.
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3 - conductivity
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- ability of an object to transfer heat or electricity to another object.
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3 - reactivity
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- the ease and speed with which an element combines, or reacts, with other elements and compounds. - reactivity decreases from left to right across the periodic table.
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3 - corrosion
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- the gradual wearing away of a metal element due to a chemical reaction.
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3 - alkali metal
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- an element in Group 1 of the periodic table; react with other metals by losing one electron - found only in compounds.
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3 - alkaline earth metal
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- an element in Group 2 of the periodic table; good conductor of electricity, react by losing two electrons.
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3 - transition metal
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- one of the elements in Groups 3 through 12 of the periodic table; iron, copper, nickel, silver & gold. Metals are hard & shiny, good conductors of electricity, form colorful compounds.
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3 - particle accelerator
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- a machine that moves atomic nuclei at higher and higher speeds until they crash into one another, sometimes forming heavier elements
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3 - alloy
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-a mixture of two or more elements, one of which is a metal.
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3 - lanthanides
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- top row of elements placed below the main part of the periodic table. - are soft, malleable, shiny metals with high conductivity
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3 - actinides
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- second row of elements placed below the main part of the periodic table. -first 4 elements occur naturally on Earth; elements heavier than uranium are created artificially.
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4 - nonmetal
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- element lacking most of the properties of a metal. - poor conductor of electricity and heat - reactive with other elements - solid nonmetals are dull and brittle
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4 - halogens
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- elements found in Group 17 of the periodic table - means "salt forming" - all but astatine are nonmetals - most reactive nonmetals
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4 - noble gases
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- elements in Group 18 - do not ordinarily form compounds because atoms do not usually gain, lose, or share electrons. - usually unreactive.
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4 - metalloids
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- an element that have some characteristics of both metals and nonmetal - most useful property is their varying ability to conduct electricity.
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4 - semiconductors
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- substances that can conduct electricity under some but not all conditions (heat, light, temperature)
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5 - plasma
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- gas-like state of matter consisting of a mixture of free electrons and atoms that are stripped of their electrons.
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5 - nuclear fusion
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- process in which two atomic nuclei combine to form a larger nucleus, forming a heavier element and releasing huge amounts of energy.
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5 - nebula
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- cloudlike region of gases left over in the remains of a shrinking, sun-sized star
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5 - supernova
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- explosion of a massive star.
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How can an element be identified?
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An element is identified by the number of protons in the nucleus of its atoms
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Who is Mendeleev?
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Russian scientist who discoverd a set of patterns that applied to all the elements.
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How is the modern perodic table organized
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The modern day perodic table is organized by the atomic number.
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How are elements arranged in groups on the periodic table?
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-There are 18 groups also called families on the periodic table -They are vertical columns
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Which group contains the most elements?
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Metals
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How can an element be predicted on the periodic table?
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by its atomic number
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How are elements in the same row alike?
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their properties change by the same pattern- reactive to unreactive to VERY unreactive
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What are some physical & chemical properties of metals?
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shininess, malleable, conductivity, reactivity & ductile
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What are the two common alkaline earth metals?
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Magnesium & Calcium
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What are transition metals?
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the elements in groups 3-12; hard, shiney, good conductors that form colorful compounds (gold, silver, copper)
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How can you know an element's reactivity using the periodic table?
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On left- most reactive ; on right- least reactive
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Where are the most reactive elements found?
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left side
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How are elements that follow uranium on the periodic table made?
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artificially in a lab
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What are some physical and chemical properties on nonmetals?
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poor conductors; solids are dull, brittle and crumble. 16 are gases
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Describe how electrical wire is made with metals and non metals.
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Inside- copper that is shaped becuse it is malleable and ductile. It has good conductivity to carry electricity. Outside is non-metal to insulate the electricity.
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What is the most useful property of metalloids?
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good semi-conductors
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What are some elements that are part of the halogen family?
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"salt-forming" chlorine, flourine, iodine
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What do scientist use to make most synthetic elements?
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particle accelorator
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What occurs during nuclear fusion in stars?
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heavier elements are made by combining smaller nuclei into larger nuclei
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What provides enough energy for nuclear fusion reactions?
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high temperature and pressure
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What is the sun made mostly of?
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hydrogen
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diatomic molecule
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- molecule consisting of two atoms. ex- Nitrogen
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Why would it be difficult to determine the properities of a newly discoverd synthetic element?
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