Chemistry I



Chemistry I

Chapter 5 & 6: A Periodic Review:

Definitions:

Valence electron: electrons in the highest occupied energy level.

Octet Rule: In forming compounds atoms tend to achieve the electron configuration of a noble gas with 8 electrons in the outer shell.

Electron configuration: the notation stating the energy level and orbital the electrons of an element occupy.

Example: Li C Cl

Li+ Cl -

Molecule, the smallest neutral unit of a substance.

Molecular compound, compounds composed of molecules.

Ion, atoms or groups of atom with a charge.

Cation. ________charged ion

Anion, ________charged ion.

Ionic compounds, compounds composed of ions (salts)

Chemical Formulas:

Show types of atoms in the smallest unit of a substance.

Show the numbers of atoms in the smallest unit of a substance.

Molecular Formula: The chemical formula of a molecular compound.

Formula Unit: the chemical formula of an ionic compound.

Monatomic Ions: individual atoms with a charge.

Charge may be identified by placement on the periodic table, Group A ions have a charge based on their placement in the periodic table.

Remember: All metals have a positive charge.

Label the periodic table below:

Group A: Representative elements.

Group B: Transitional and inner transitional metals

Alkali Metals Other metals

Alkaline Earth metals Group 7A halogens

Metalloids Noble Gases

Dimitri Mendeleev is responsible for the basis of what is now the Periodic Table.

1A 2A --------------B--------------------------- 3A 4A 5A 6A 7A 8A

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Vocabulary:

Valence Electrons: electrons found on the outer shell of an atom. These electrons are responsible for the chemical properties of an atom.

Core Electrons: the electrons found closer to the nucleus, not responsible for atomic bonding.

Representative Elements: Group A, The outermost shell is made of electron in the s or p orbital. The number of the group corresponds to the number of valence electrons.

Transition metals: Group B, The outer most shell is made of electrons in the d orbital. The inner transition metals have valence electron in the f orbital.

Ionization Energy: the energy required to remove a valence electron form an atom or ion.

Electronegativity: the tendency for an atom of an element to gain an electron.

Look at the tables below. Notice the trends in different chemical properties as one moves along the groups and periods.

Atomic Radius: increases as one moves down a group due to the increase in energy shells, but decreases as one moves across a period due to the increase in the number of protons in the nucleus.

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Ionization energy: decreases as one moves down a group due to the increase in energy shells and increase in distance a valence electron is from the nucleus. Increases as one moves across a period as atom gets closer to noble gas configuration.

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Electron affinity: decreases as one moves down a group and increases as one moves across a period. F has the highest electronegativity in table.

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Label the table below identifying the group A columns and their associated charge:

Reminder:

Lewis dot of common elements:

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How Ionic is your Bond??

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Find the difference in the electronegativity of the two atoms in the bound compound.

0 to 0.6 less than 10% ionic the item is a non-polar molecule.

0.7 to 1.6 with 12 to 47 % ionic and the item is polar covalent.

1.7 to 3.2 is 51 to 92 % ionic and the item is ionic.

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