9/20/2017. Elements are Pure Substances that cannot be broken down into simpler substances by chemical change (contain Only One Type of Atom)

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CAPTER 6: TE PERIODIC TABLE Elements are Pure Substances that cannot be

Type of Atom) The Periodic Table (Mendeleev) In 1872, Dmitri Mendeleev

properties and placed them in order of increasing mass.

that Medeleev left for them in his classification scheme.

Mendeleev s Periodic Table Two Numbering Systems for Groups The old method

for the transition elements (the 10 short columns in the middle).

1 CAPTER 6: TE PERIODIC TABLE Elements are Pure Substances that cannot be broken down into simpler substances by chemical change (contain Only One Type of Atom) The Periodic Table (Mendeleev) In 1872, Dmitri Mendeleev arranged the 60 elements known at the time into groups with similar properties and placed them in order of increasing mass. e left empty spaces for 3 elements that he suspected existed but that had not yet been discovered. Eventually, the 3 elements were discovered and fit in the exact places that Medeleev left for them in his classification scheme. The Modern Periodic Table Groups contain elements with similar properties and are arranged in vertical columns. Periods are the horizontal rows of elements. Mendeleev s Periodic Table Two Numbering Systems for Groups The old method uses the letter A for the Main group elements (1A to 8A) and the letter B for the transition elements (the 10 short columns in the middle). Alkali Metals Soft, shiny metals Low melting points Good conductors React with water to form basic solutions Special Names of Groups The new method numbers groups 1 18 from left to right. Exist as two atoms joined together Very reactive alogens 1

The Unusual Nature of Carbon Carbon s ability to join with itself and other elements ives it a versatility not seen with any other

Elemental forms of carbon include the following carbononly structures: Diamond Graphite Shape of the Periodic Table with Lanthanides

separates metals and nonmetals. Metals are located to the left. Nonmetals are located to the right.

and Metalloids Metals Metalloids Nonmetals Shiny (s) except g (l) Dull (s, l, g) Ductile, malleable Brittle Name an element in the

Li Be B C N O e F Ne Good conductors of heat and electricity Better conductors than nonmetals, but not as good as metals Good

2 The Unusual Nature of Carbon Carbon s ability to join with itself and other elements ives it a versatility not seen with any other element in the periodic table. Elemental forms of carbon include the following carbononly structures: Diamond Graphite Shape of the Periodic Table with Lanthanides and Actinides (aka Inner Transition Elements) Inserted Into the Main Section Metals, Nonmetals, and Metalloids The heavy zigzag line separates metals and nonmetals. Metals are located to the left. Nonmetals are located to the right. Metalloids are located along the heavy zigzag line between the metals and nonmetals (except for Al) Properties of Metals, Nonmetals, and Metalloids Metals Metalloids Nonmetals Shiny (s) except g (l) Dull (s, l, g) Ductile, malleable Brittle Name an element in the periodic table that you would expect to be chemically similar to sulfur. Li Be B C N O e F Ne Good conductors of heat and electricity Better conductors than nonmetals, but not as good as metals Good insulators (poor conductors) Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La f Ta W Re Os Ir Pt Au g Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh s Mt Ds Rg Ce Pr Nd Pm Sm Eu Gd Tb Dy o Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Metals Metalloids Nonmetals 2

3 Classification of the Groups Representative elements Of the following which would not be considered a metalloid? Li Be Na Mg K Ca Transition elements Sc Ti V Cr Mn Fe Co Ni Cu Zn B C N O e F Ne Al Si P S Cl Ar Ga Ge As Se Br Kr 1. Ge 2. Sb 3. Se 4. Did I miss something? What is a metalloid? Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La f Ta W Re Os Ir Pt Au g Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh s Mt Ds Rg Inner transition elements Ce Pr Nd Pm Sm Eu Gd Tb Dy o Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr The element found in the 6A family (or group 16) and period four can be toxic and a micronutrient. What is the symbol for that element? 1. Sb 2. As 3. Se 4. Te What element in the alkaline earth family has an atomic number that is the average of the element directly above and below it on the periodic table, and is in the fifth period? 1. Mg 2. Na 3. Rb 4. Sr The chemical properties of an element depend on the number of electrons in the valence shell. Elements in the same group have the same number of valence electrons Group # 1A 8A = # valence electrons (except e = 2) The valence shell is the outermost shell (highest value of n) The electrons in the valence shell are called valence electrons. Ex: All elements in Group 2A have 2 valence electrons. Be 1s 2 2s 2 valence shell: n = 2 # of valence electrons = 2 Cl 1s 2 2s 2 2p 6 3s 2 3p 5 valence shell: n = 3 # of valence electrons = 7 3

Electron-Dot Symbols Dots representing valence electrons are placed on the four sides of an element symbol.

The electron-dot symbol of Mg shows two valence electrons as single dots on the sides of the symbol Mg.

The electron-dot symbols for Groups 1A(1) to 4A(14) use single dots Na Mg Al C Groups 5A(15) to 7A(17) use pairs and single dots.

distance from the nucleus to the valence electrons Periodic Trends in Atomic Size The size of atoms i creases do a co um, as the valence

The size of atoms decreases across a ro, as the number of protons in the nucleus increases, pulling the valence e in closer.

4 Electron-Dot Symbols Dots representing valence electrons are placed on the four sides of an element symbol. Each dot represents one valence electron. The electron-dot symbol of Mg shows two valence electrons as single dots on the sides of the symbol Mg. Mg or Mg or Mg or Mg For 1 to 4 valence electrons, single dots are used. With > 4 valence electrons, the dots are paired. The electron-dot symbols for Groups 1A(1) to 4A(14) use single dots Na Mg Al C Groups 5A(15) to 7A(17) use pairs and single dots. P : O Element: # of Valence electrons: 1 C 4 O 6 Cl 7 Electron-dot symbol: C O Cl Atomic Size is described using the atomic radius is the distance from the nucleus to the valence electrons Periodic Trends in Atomic Size The size of atoms i creases do a co um, as the valence e are farther from the nucleus. The size of atoms decreases across a ro, as the number of protons in the nucleus increases, pulling the valence e in closer. Which has a larger size, C or O? C is bigger than O. C has 6 protons in the nucleus for a + 6 charge at the nucleus, while O has 8 protons in the nucleus, for a +8 charge at the nucleus. Which has a larger size, Li or K? K is bigger than Li. K has a valence electron in energy level 4 while Li has a valence electron in level 2. This means the K atom is larger than the Li atom because the valence electron is farther away from the nucleus. 4

Which has a larger size, C or Al? Both trends indicate that Al is larger than C. Going across the size decreases so C is smaller than Al, and going down the size increases so Al is bigger than C.

The first Ionization energy is the energy needed to remove an electron from an atom.

5 Which has a larger size, C or Al? Both trends indicate that Al is larger than C. Going across the size decreases so C is smaller than Al, and going down the size increases so Al is bigger than C. Which has a larger size, Se or I? I is bigger than Se. The increase in size going down a group is bigger than the decrease in size going across a group. The first Ionization energy is the energy needed to remove an electron from an atom. Na + energy Na + + e Increases Decreases Ionization energies decrease down a column as the valence e get farther away from the positively charged nucleus. The 1 st ionization energy increases as you go left to right across a row as the number of protons in the nucleus increases. Ionization energies increase across a row as the number of protons in the nucleus increases. The 1 st ionization energy decreases as you go down a group as the distance between the nucleus and valance electrons increases. Which has the higher ionization energy, As or Sb? As has a higher ionization energy than Sb, according to the top-to-bottom ionization trend in the periodic table. 5

Which has the higher ionization energy, N or Si? N has a higher ionization energy than Si, according to both the top-to-bottom and the left-to-right ionization trends in the periodic table.

ere we can't tell which has the higher ionization energy: O would be higher according to the top-to-bottom trend, but Cl would be higher according to the left-toright ionization trend.

Na Mg Al Si P S Cl Ar The elements get less metallic as you go left to right. Which is the more metallic element, Sn or Te?

The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions.

6 Which has the higher ionization energy, N or Si? N has a higher ionization energy than Si, according to both the top-to-bottom and the left-to-right ionization trends in the periodic table. Which has the higher ionization energy, O or Cl? ere we can't tell which has the higher ionization energy: O would be higher according to the top-to-bottom trend, but Cl would be higher according to the left-toright ionization trend. The effects tend to cancel. C Si Ge Sn Pb Trends Within the Periodic Table Metalocity: how metallic the element is. The elements get more metallic as you go down a group. Na Mg Al Si P S Cl Ar The elements get less metallic as you go left to right. Which is the more metallic element, Sn or Te? Sn is a more metallic element than Te, according to the leftto-right metallic character trend in the periodic table. The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends. Metals Metalloids Nonmetals Using these generalizations, francium is the most metallic element while helium is the least metallic. Which is the more metallic element, Si or Sn? Sn is a more metallic element than Si, according to the topto-bottom metallic character trend in the periodic table. Which is the more metallic element, Br or Te? Te is a more metallic element than Br, according to both the top-to-bottom trend and the left-to-right metallic character trend in the periodic table. 6

7 Which is the more metallic element, Se or I? ere we can't tell which has the greater atomic size: I would be more metallic according to the top-to-bottom trend, but Se would be more metallic according to the left-to-right metallic character trend. The effects tend to cancel. 7

The Periodic Table of Elements

The Periodic Table of Elements 8 Uuo Uus Uuh (9) Uup (88) Uuq (89) Uut (8) Uub (8) Rg () 0 Ds (9) 09 Mt (8) 08 Hs (9) 0 h () 0 Sg () 0 Db () 0 Rf () 0 Lr () 88 Ra () 8 Fr () 8 Rn () 8 At (0) 8 Po (09)