Ch Notes---Atomic Properties and the Periodic Table Valence Electrons and Electron Dot Notations What are “valence electrons”? These are the electrons in the _________-_______ energy level (or shell). These are responsible for chemical bonding. All of the other electrons are called “core electrons”. They will be “___” electrons and “___” electrons only. Counting Valence Electrons Group A # = number of valence electrons (only exception Helium = __ e - ’s) Examples: Ca = __ e - ’sNitrogen = __ e - ’sArgon = __ e - ’s d-block and f-block = ___valence e - ’s outermost s p

Drawing Valence Electrons “Electron-dot notation”: Electrons will be represented as dots located around the symbol of the element in the pattern shown below. Examples: Nitrogen = Hydrogen = (important exception.... Helium = ) X NH He

Carbon’s Hybrid Orbital C …___ ___ ___ ___ (Before) 2s 2p ↓ ↑↑ ↑ C …___ ___ ___ ___ (After: 4 covalent bonds available) ↑↑↑↑ Practice Problem: Draw the electron dot notation for Carbon: 2sp 3 C

Valence Electrons On The Periodic Table Sucktastic! Assume 2 Son of Sucktastic! Assume 2

The Development of the Periodic Table _________________________: constructed the 1 st periodic table Features of Mendeleev’s Periodic Table He left ______ _________ for “missing elements”. Later when these elements were discovered, he filled in the gaps. He arranged the elements in columns and rows according to their __________________. Elements with similar properties were in the same horizontal row. He was able to accurately ___________ the properties of the missing elements based on the properties of the elements in similar _______. He ordered the elements by increasing __________ ___________. Dmitri Mendeleev blank spaces properties predict rows atomic mass

Mendeleev’s Periodic Table

Features of the Modern Periodic Table In 1913, Henry ______________ determined the atomic number, (# of ___), of the elements. – He then arranged the elements in the periodic table by increasing atomic ____________. – This switched the position of some elements. This is how the modern periodic table is arranged today. In 1942 Glenn T. ________ rearranged the periodic table to include the 5f row. He won a Nobel Prize after publishing his new periodic table. Horizontal Rows = ____________ or Series Vertical Columns = ____________ or Families Elements in the same _________/_________ have similar properties. Moseley number p+p+ Periods Groups groupsfamilies Seaborg

Figure 11.35: Classification of elements as metals, nonmetals, and metalloids.

Parts of the Periodic Table Metals: located to the _______ of the dark zig-zag line running through the “p-block”. This includes the elements in the ___-block. Properties of Metals – shiny surface – ______________ (you can pound it into a flat sheet) – ______________ (you can draw it into a thin wire) – good _______________ (heat/electricity travels through it easily) left f malleable ductile conductors

Parts of the Periodic Table Nonmetals: located to the ___________ of the dark zig-zag line. Properties of Nonmetals – _______ surface – ______________ – good _______________ (or poor conductors) Metalliods: located on the border of the dark zig-zag line. Examples: Silicon & Germanium Properties of Metalliods – ___________________ right dull brittle insulators semiconductors(Used in computer chips) sulfur

Parts of the Periodic Table d-block metals: “_________________ metals” f-block metals: “Inner-transition metals” or “____________ metals” Special Group/Family Names Group 1A: “_________ metals” – React with _________ to form a base Group 2A: “________________ metals” – Compounds are used in batteries Group 7A: “_________________” – Used in some light fixtures Group 8A (or 0 or 18): “_______ gases” – Don’t form compounds (_________) transition rare-earth Alkali water Alkaline-earth Halogens Noble inert

Parts of the Periodic Table Inner- transition metals

Parts of the Periodic Table

Trends in the Periodic Table Atomic Size (Atomic Radius) (See Fig ) Moving Down a Group= the size of the atoms ________________ – Why? You are adding ________ of electrons to higher and higher energy levels (farther and farther out.) Moving Across a Period= the size generally ______________ – Why? You are adding more e - and p + to the same energy level. This causes more ______________ of opposite charges and it __________ the electron cloud inward. increases more decreases attraction pulls

Figure 11.36: Relative atomic sizes for selected atoms.

Trends in the Periodic Table Atomic Size vs. Ion Size (See Figure 12.8) Cation = (___) charged atom created by ___________ e-’s. – Cations are ______________ than the original atom. – _____________ generally form cations. Anion = (___) charged atom created by _____________ e-’s. – Anions are ____________ than the original atom. – _______________ generally form anions. + removing smaller Metals − adding larger Nonmetals

Trends in the Periodic Table Atomic Size vs. Ion Size

Figure 12.8: Relative sizes of some ions and their parent atoms. picometers

Ionization Energy Ionization energy is the energy required to _______________ the outer most electron in an atom. Moving Down a Group= _______________ (less energy is needed) – Why? You are trying to remove an electron that is farther and farther out (for larger and larger atoms). These e - ’s are not as ________________to the nucleus. – In general, the larger the atom, the ____ attracted it is to its e - ’s. Trends in the Periodic Table remove decreases attracted less

Ionization Energy Moving Across a Period= generally ________________ – Why? Moving across a period takes us from metals to nonmetals. More ionization energy is needed for ______________ compared to __________. – Also, since metals generally form _________, it won’t take as much energy to remove it’s outer most electron. – Remember that as you move across the period, the atoms get _________ and therefore ______ attracted to the electrons. Trends in the Periodic Table increases nonmetalsmetals cations smallermore

First Ionization Energies

“Successive Ionization Energies” “Successive Ionization Energies” means the energy required to remove a _____ or a _____ electron from an atom. – Removing more and more e - ’s requires ______ and ______ energy. – Why? The remaining e - ’s are more _________ _________ to the nucleus. Trends in the Periodic Table 2 nd 3 rd more tightly bound

Electronegativity (See Figure 12.4) Electronegativity is a relative value (from_________) which compares how much an atom is attracted to the e - ’s in a ____________ bond. Moving Down a Group= generally ______________ (less attraction) – Why? The bonded electron is farther and farther out. These e - ’s will not be as attracted to the larger and larger atoms. Trends in the Periodic Table 0 – 4.0 chemical decreases

Figure 12.4: Electronegativity values for selected elements.

Electronegativity Moving Across a Period= generally _________________ – Why? Again, the atoms are getting ________ so they are _______ attracted to the bonding electrons. – Also, moving across a period takes us from metals to nonmetals. Since nonmetals generally form _________, they tend to __________ e - ’s anyway, and this makes them ________________ attracted to e - ’s when forming a chemical bond. – ___________ __________ are not listed in Figure 12.4 since they do not ________ _____________ ! Trends in the Periodic Table increases smaller more anions gain highly Noble gases form compounds

Determining the Ion Formed Atoms try to achieve a ________ ______ configuration when forming an ion. (This makes them more stable.) – Locate the nearest noble gas and count how many “places” it is away, but remember that you can skip over the d-block!! – This amount will be the same as the # of e - ’s either gained or lost by the atom when forming an ion. Practice Problem: How many electrons are gained or lost when forming an ion from the following elements? a) Magnesium: ____ (gained or lost) b) Iodine: ____ (gained or lost) c) Gallium:____ (gained or lost) d) Boron:____ (gained or lost) noble gas 21 33

Practice Problems: 2) a) Draw the electron dot notation for a potassium atom. b) Draw the electron dot notation for a potassium ion. 3) a) Draw the electron dot notation for a sulfur atom. b) Draw the electron dot notation for a sulfur ion. K [K +1 ] S [ S -2 ]