Atomic and Molecular Structure

1. Atomic and Molecular Structure Austin Bacong, Angelica Lai, Heris Santos, Kyle Solano Mr. Pilakowski Period 2 Honors Chemistry

2. Vocabulary • Alkali Metals- Group 1 metals • Alkaline Earth Metals- Group 2 metals • Atom- The fundamental unit of which elements are composed • Atomic mass-the weight average mass of the atoms in a naturally occurring element. • Atomic number-the number of protons in the nucleus of an atom • Electronegativity-the tendency of an atom in a molecule to attract shared electrons to itself. • Electrons-negative components of an atom that circle the nucleus in an orbital • Family-elements in the same vertical column of the periodic table. • Protons- Positive particles that make up the nucleus

3. Vocabulary (cont.) • Halogens-Group 7 element. • Ionization energy-the quantity of energy required to remove an electron from a gaseous atom or ion. • Ions-atoms that have become a charged entity by gaining or losing an electron • Isotopes-atoms of the same element that have different numbers of neutrons. They have identical atomic numbers but different mass numbers. • Mass-the quantity of matter in an object. • Neutrons-a particle with no net charge that is located in the nucleus of an atom • Nonmetals-an element that does not exhibit metallic characteristics. • Nucleus-the positive core of an atom made up of protons and neutrons • Orbital-a point in space around an atom where an electron may be found.

4. Vocabulary (cont.) • Semimetals(metalloids)-elements that share properties both with nonmetals and metals • Transition metals-38 elements found in groups 3-12 on the periodic table • Valence electrons-electrons that have reached the outermost energy level(the valence shell) • Valence shell-the outermost energy level • Bohr model-a model that proposes an atom is made up of a positive core(nucleus) and electrons circle it in fixed orbits

5. California Chemistry Standards • Standard 1a: Students know how to relate the position of an element in the periodic table to its atomic number and atomic mass • Standard 1b: Students know how to use the periodic table to identify metals, semi metals, non-metals, and halogens • Standard 1c: Students know how to use the periodic table to identify alkali metals, alkaline earth metals, transition metals, trends and ionization energy, electronegativity, and relative sizes of ions and atoms. • Standard 1d: Students know how to use the periodic table to determine the number of electrons available for bonding. • Standard 1e: Students know the nucleus of an atom is much smaller than the atom yet contains most of the atom’s mass.

6. As you go down a family,elements tend to become heavier and increase in atomic size. Standard 1a 8 refers to the element’s atomic number As you go across a period, elements tend to become heavier and decrease in relative size 16.00 refers to the element’s mass number

7. Standard 1b • Metals are found in families 1 and 2 • The transition metals are found in families 3- 12 • Semi metals are elements 5, 14, 32, 33, 51, 52, and 84 • Halogens are in family 17 • Non- metals are found in a diagonal to the right from element 6 to 86. • Nonmetals: high ionization and elctronegativity, are poor conductors of heat and electricity and are brittle • Metals: shiny, good conductors of heat and electricity, malleable, and ductile. • Semi metals: metallic luster, are good semi conductors and have the same properties as metals and non metals. • Halogens: very high electronegativities, are highly reactive, and have seven valence electrons.

8. Standard 1c • Red: alkali metals • Light brown: alkaline earth metals • Orange: transition metals As you move down, electronegativitydecreases As you go across a period, electronegativityincreases.

9. Standard 1d • The column number on the periodic table shows the number of valence electrons for the atom in that column. • Column 8, or the noble gases, don’t react because the outer rings of the atoms aren’t filled completely Aufbau- Electrons in lowest energy level Hunt- Electrons fill one orbital before filling others Pauli Exclusion- Orbitals must have two opposite spins Elements want to be like noble gases with all eight valence electrons though bonding

10. Standard 1e • Earnest Rutherford • tin foil experiment • “where is most of the atom’s mass located?” • the nucleus is the densest part of the atom • contains most of the mass • positively charged. The deflected particles proved that the atom is made up of mostly empty space and that most of the mass is located in the nucleus.

11. Summary of Rules Know: • Special properties of each type of metal • Periodic table trends; ex. Electronegativity increases when going across and decreases when goes down the periodic table. • Rules for valence electrons and how to identify how many valence electrons there are for each element based on the family • How to locate elements based on their masses and number • The mass of the electron is contained in the nucleus

12. Resources • “Periodic Table” Chemeddl. N/A. 31 May 2009 http://www.chemeddl.org/collections/TSTS/PeriodicTable.gif • “Periodic Table – Alkali Metals” Boomeria. N/A. 1 June 2009 <http://boomeria.org/chemlectures/periodictable.jpg> • “Valence Electrons” Mansfieldct. N/A 1 June 2009 http://www.mansfieldct.org/schools/mms/staff/hand/Valence.gif • “Rutherford’s Experiment” Nisd. 2008 October 1 June 2009 <http://www.nisd.net/marshall/Departments/Sciencedept/Atomic%20Theory/Images/GoldFoilExpt.gif >