Chapter 6 The Periodic Table Stylish Shoes Mr Samaniego Lawndale High School

What is in common with all the pictures below?

Which one does not belong?

Which one does not belong?

Which one does not belong?

Which one does not belong?

Section 6.1 - Organizing the Elements The discovery of elements has been an ongoing process since ancient times By the 1700’s, only about 13 elements had been identified In the 1800’s, there were only 31 known elements By 1865, that number had more than doubled to 65 known elements

History of the Periodic Table In 1869, Dmitri Mendeleev published a classification scheme of all the currently known elements Mendeleev insisted that elements with similar characteristics be listed in the same family He also left blank spaces in his table for undiscovered elements

Mendeleev’s Periodic Table Chemists used the properties of elements to sort them into groups (columns) From 1829 to 1869, many other scientists proposed different systems, but none gained wide acceptance In 1869, Dmitri Mendeleev arranged the elements in his periodic table in order of increasing atomic mass AND repeating properties

Mendeleev’s Periodic Table (1869)

Albert Tarantola’s Orbital Table                                                                            

Timothy Stowe – Table for Physicists                                                      

Theodor Benfey                                                                            

Emil Zmaczynski                                                        

Vocational Exile Periodic Table

The Periodic Law About 40 years later, Henry Moseley determined atomic numbers for each known element so… In the modern periodic table, elements are arranged in order of increasing atomic number The Periodic Law states that when elements are arranged in order of increasing atomic number, there is a trend in their physical and chemical properties

Metals, Metalloids and Nonmetals (Red or Black “Ladder” on the periodic table aka zigzag line) Elements can be grouped into three broad classes based on their general properties Metals Nonmetals Metalloids

Metals: elements that are generally solid at room temperature, have a grayish color and shiny surface, and conduct heat and electricity

Nonmetals: elements that have varying properties but are generally poor conductors of heat and electricity

Metalloids: elements with some properties of metals and nonmetals

Section 6.2 - Classifying the Elements (Page 162-163) The periodic table displays the symbols and names of the elements, along with information about the structure of their atoms (# of protons, neutrons and electrons)

Groups and Periods on the PT

Element that are solid at R. T Element that are solid at R.T. are usually printed in black, liquid at R.T. printed in blue, and gases at R.T. are printed in green

Periodic Table at Different Temperatures

The 8 Groups of the Periodic Table Hydrogen Alkali Metals (Group 1A) Alkaline Earth Metals (Group 2A) Chalcogens (Group 6A) Halogens (Group 7A) Noble Gases (Group 8A) Transition Metals (Group B) Inner Transition Metals (Lanthanides and Actinides)

Practice Which group are the following elements in? Fluorine Calcium Iron Oxygen Krypton Lithium Uranium Hydrogen

Electron Configurations in Groups Elements can be sorted into different groups based on their electron configuration Noble Gases always have their s and p orbital completely filled with electrons, which makes them relatively inactive

Representative Elements Representative Elements are Groups 1A through 7A because they display a wide range of physical and chemical properties

Section 6.3 – Periodic Trends Properties of elements are related to their location on the periodic table We will be studying 3 periodic trends: Atomic Radius Ionization Energy Electronegativity

1. Atomic Radius or Atomic Size One-half the distance from center to center of two atoms Atomic Radius

Atomic Radius or Atomic Size What do you notice about the atomic radii of the elements on the periodic table? Atomic Radius increases towards the bottom left corner of the PT

Atomic Radius/Size Practice Which element has a greater atomic radius? F or Cs Ga or K Kr or Rb Ba or Si Fr or W O or Ag

Ions Remember that neutral atoms have the same number of protons and electrons When elements combine in compounds, they do not have the same number of protons and electrons anymore Ions are atoms that have a positive or negative charge.

Positive and negative ions form when electrons are transferred between atoms (given up or stolen away) Cations Cation – an ion with a positive charge (lost electrons)

Anions Anion – an ion with a negative charge (gained electrons)

Ionic Size Cations are always smaller than the atoms from which they form Anions are always larger than the atoms from which they form

Practice Which of the following is larger? Na or Na+ Al or Al3+ I or I- Ca2+ or Ca S or S2- O2- or O

2. Ionization Energy The energy required to remove an electron from an atom

Ionization Energy What trend do you notice about the ionization energy of the elements on the periodic table? Ionization Energy increases towards the top right corner of the PT

Ionization Energy Practice Which of these elements has a greater ionization energy? Kr or Ar Al or Na S or Rb Si or Cs He or Ca P or O

3. Electronegativity The ability of an atom to attract electrons to itself when in a compound

Electronegativity What trend do you notice about the electronegativity of the elements on the periodic table? Electronegativity increases towards the top right corner of the PT

Electronegativity Practice Which element has greater electronegativity? Na or F Ca or C Al or Mg Sr or Al Ca or K Cl or F