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Periodic Table and Periodic Trends Chapter 14 Periodic Table • A table that organizes the elements in order of increasing ________ ________ and by similar chemical and physical properties • ___________ ____________, Z – The number of _________ in the nucleus of an atom. – It determines the __________ of the atom. Periods / Series • ______ on the periodic table • Represent the ________ that the valence electrons occupy. • Valence Electrons – ____________ electrons in an atom. – The electrons that are lost, gained, or shared in chemical reactions. – The _________ ________ ________ in an element's outer shell determines the chemical properties of that element. Li (Z=3) Be (Z=4) B (Z=5) Groups/Families • Columns • All elements in the same group have the same number of ________ _________, and therefore have similar __________ properties. • Some groups have special names Li (Z=3) Na (Z=11) K (Z=19) Special Groups • • • • Group 1 Group 2 Group 7 Group 8 - • In addition some regions of the periodic table have special names. Metals • Located on the _____ side of the periodic table. • _______ ________ ________ in chemical reactions. • ________, ________, ________, ________ • Transition metals. Nonmetals • Located on the _____ side of the periodic table. • ______, ________ • _______ ______ in chemical reactions. • ________ ______: Every atom wants __ valence electrons. Metalloids • Located on the stairstep line. • Have metallic and nonmetallic properties. • B, Si, Ge, As, Sb, Te, and Po Blocks • Based on electron configurations • Named after the sublevels that are being filled. Na (Z=11) O (Z=8) Cu (Z=29) Representative Elements • ___-block and ___block elements. • Lewis Dot Diagrams – Dots represent v. e– One dot per v. e– Only used with rep. elements Development of the PT • Дмитрий Менделеев • Lothar Meyer • Henry Moseley Periodic Trends • A ________ ____________ variation in elements’ properties due to regular variations in atomic structure. • • • • _____________ ___________ _____________ ___________ _____________ ___________ _____________ Atomic Radius • The “______” of an atom. • Determined by the ________ _________. • There are different ways to define atomic radius. • 1/2 the distance between two bonded nuclei. Trend in Atomic Radius Trend in Atomic Radius • _________ across a period. – Adding protons which pull the electrons in. • __________ down a group. ___________ Radius – Core electrons “shield” the outer electrons from the attractive force of the nucleus. ____________ Radius Ions, Cations, and Anions • Ion – An atom that has ______ or _______ electrons. – A _________ atom* • Cation – A ____________ charged ion. – An atom* that has _______one or more electrons. • Anion – A __________ charged ion. – An atom* that has gained one or more electrons Ionic Radius Ionic Radii. (2008). NCSSM D.E.T T.I.G.E.R. (chemistry, periodic trends, ionic radii) [Chemistry Animations and Slides for Math and Chemistry]. Retrieved April 25, 2009, from North Carolina State School of Science and Mathematics Distance Education Technologies Web site: http://www.dlt.ncssm.ed u/tiger/ Ionic Radius • Cations are _______than the parent atom. – The __________ to ___________ ratio ___________ and the attraction on the remaining electrons _____________. • Anions are _________ than the parent atom. – The ___________ to __________ ratio __________ and the attraction on the electrons ______________. • Isoelectronic Ionization Energy • The _________ ________ needed to _________ an electron from a ground state ________ atom or ion. Na(g) Na (g) e Na(g) Na (g) e Na (g) Na2 (g) e I1 496 I2 4560 Succesive Ionization Energies • First Ionization Energy, I1 Na(s) Na (g) e I1 496 kJ/mol • Second Ionization Energy, I2 Na (g) Na (g) e • I1 < I2 < I3 <… 2 I2 4560 kJ/mol Successive IEs Trends in Ionization Energy • ____________ across a period – Atomic radius ____________ and the pull on the electrons ___________. – Smaller atoms have a greater attraction for electrons, thus a higher ionization energy. Trends in Ionization Energy • ____________ down a ___________ – Adding more ________ _______ = more _______, and the size of the atom __________. – As the size of the atom increases the “pull” on the electrons decreases and thus ionization energy decreases Irregularities in IE Electronegativity • The ability of an atom in a molecule to __________electrons to itself. • Can be used to predict how equally electrons are shared in a bond. • Calculate the electronegativity difference. • Values range from 0 to 4 Difference Bond Type What’s happening 0 to 0.4 Nonpolar covalent Equal sharing Between 0.4 and 1.7 Polar covalent Unequal sharing Greater than 1.7 Ionic Electron transfer Trends in Electronegativity ____________across a _____________ – Atomic radius _________ and the pull on the electrons __________. – Smaller atoms have a greater _________ for electrons, thus a higher ___________. Trends in Electronegativity • ____________ down a __________ – Adding more _______ _______ = more _________, and the size of the atom increases. – As the size of the atom __________, the “pull” on the electrons ____________ and thus electronegativity ___________.