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The Periodic Table Chapter 5. Organizing the Elements. A few elements, such as gold and copper, have been known for _________ of years - since _________ times Yet, only about ___ had been identified by the year __________. Organizing the Elements.
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Organizing the Elements • A few elements, such as gold and copper, have been known for _________of years - since _________ times • Yet, only about ___had been identified by the year __________.
Organizing the Elements • Duringthe _________century, chemists began to categorize the ______________ according to similarities in their ________________________________. The end result of these studies was our modern _____________________.
Mendeleev’s Periodic Table • By the _____________, about _____ elements were known to exist • ____________________ – a Russian chemist and teacher • Arranged elements in order of increasing ___________________ • First “__________________” credited to him • Predicted existence of ______________elements
Mendeleev • leftblanksfor____________________ • stated that if the atomic weight of an element caused it to be placed in the ____________, then the weight must be ____________. (He corrected the atomic masses of Be, In, and U) • was so confident in his table that he used it to predict the _______________ of three elements that were __________ at the time.
Mendeleev • After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev’s predictions for ____, _____, and _______were amazingly close to the ______________values, his table was generally accepted.
A better arrangement • In 1913, ________________, a British physicist, arranged elements according to increasing __________ ______________. • This arrangement is used today. • The _________, ________________& _______________________are basic items usually included on the P.T.
Periodic Table Introduction • The arrangement of the ___________show how _______________________can be related. • The arrangement shows the relationship between ________________and ___________________. • The elements are arranged in order of increasing ____________reading from _____________and from __________________________. • Atomic number is the number of ___________ in the nucleus of the atoms of an element.
Groups • A group (or _______) is a ______________on the PT. • Each group has the same number of _____________. • Valence means ___________electrons (outer energy level). • This gives the group similar _____________properties. • The groups are numbered from ___to ____.
More About Groups • The ones column of the group number is the same as the ___________________________for the neutral atom of that element. • Example: carbon is in group 1__ and has ___ valence electrons • Usually the noble gases are thought of as having ___valence electrons. This means the outermost energy level is ___________________. This is believed to be why they have very, very little ______________________.
Periods • A period is a _______in the periodic table. • Periods are numbered ________. • Each period corresponds to a new ___________ __________. • The first element in each period has only ____ _______________ in its outer shell. • The second-to-last element in the period only ________one more electron to fill the ________.
Periodicity • Periodicity is the regular ___________________ according to the arrangement of ___________in the periodic table. • Chemical and physical properties of elements show periodicity if the elements are arranged in order of _____________________________. • This is the modern “___________________”.
Metals • Found ___________________of the PT • Good conductor of ______________________ • Most metals have _________(tend to be shiny). • Most metals are _________at room temperature. • Most have the property of ______________(can be hammered or rolled into thin sheets). • Most are ________________(can be drawn into a wire).
Nonmetals • _______________side of PT • _____________conductor of heat and electricity • Many are ____________at room temperature. • One nonmetal, bromine, is a ____________. • Solid nonmetals include C, P, Se, S, and I. They tend to be __________________.
Metalloids • A ______________is an element that has some characteristics of ________________and some characteristics of _____________________. • Less malleable than metals, but not as brittle at nonmetals • Tend to be ________________________ • Used in computers, digital watches, TV, and radios • Remember the “staircase”. (Next slide)
Groups of Elements – Family Names • Group 1 – __________________ • Forms a “_____” (or alkali) when _________ with water (not just dissolved!) • Group 2 – ____________________ • Also form bases with water; do not dissolve well, hence “earth metals” • Group 17 – _____________ • Means “salt-forming” • Group 18- ___________________ • Formerly “_______Gases”- Very ______________
Sections of the P.T. • __________ are the elements in Group 18 • Previously called “__________gases” because they rarely take part in a reaction; ____________= __________ • Noble gases have an electron configuration that has the outer s and p sublevels _____________________.
_____________________are in Groups 1,2 then 13 to 18 • Display ___________of properties, thus a good “representative” • __________- Include metals, or nonmetals, or metalloids; Include solid, liquids and gases. • Their outer electron configurations are _____________________________.
_____________are in the “___” block of groups ___through ____. • Electron configuration has the outer s sublevel full, and is now filling the “__” ________________. • A “___________” between the metal area and the nonmetal area • Examples are gold, copper, silver
_____________________are located below the main body of the table in two horizontal rows • ________________and _____________ • Filling the _________________ • Formerly called “__________________” elements • Set at the bottom to keep P.T. from being too wide.
