Across a Period, Atomic Radii Tends to ______ from Left to Right

Trends of the Periodic Table

1. Atomic Radii

•atomic radii (atom _____) is determined by measuring the ______between the ______of 2 ______ atoms that are chemically bonded together, then ______this distance by ___.

• measured in pm (______, or 10-12 m).

•across a period, atomic radii tends to ______ from left to right.

•this is due mostly from the increase in ______.

•as electrons are added to the __and__ sublevels, they are pulled ______and closer to the ______, which results in a decrease in atomic radii.

•down any ______ on the table, the atomic radii will ______.

•this is due to an ______in total number of ______ (protons, neutrons, and especially ______) in the atom. The number of ______needed increases, so the overall size increases.

•also, the electrons that are added to these ______ elements are being added in orbitals that lie farther and farther away from the ______, and thus, father away from any ______ charges that would bring them ______inside and ______ the radii.

•thus, the overall trend line for atomic radii looks like the figure to the right.

•the placement of the ______in the ______corner of the table indicates that you will find the ______elements there.

•note that ______(F) is one of the ______elements.

2. Ionization Energy

•ionization energy is the energy required to ______one electron from an atom, forcing the creation of a ______ ion.

•for example, if you were to remove the ______that sodium (Na) has in its ______s and p orbitals, you would create an _____ ion.

•any process that refers to the ______of an ____ is called ______.

•IE is measured in ______per ______ (kJ/mol), which is a unit that represents ______required per ______ of substance.

•across a period from left to right, IE will generally ______.

•this is due mostly to the number of ______electrons that can be found in their outermost s and p orbitals.

•the ______ the number, the easier it is to ______ them.

•therefore, the ______will lose electrons very ______ (only ___ to lose) and have _____ IE, and......

•the ______ (with ___ valence e-) will hold onto those electrons for dear life, and have very ______IE.

•this explains why the alkali metals are very ______ with most substances, and noble gases are the most ______ elements.

•the reason that ______ equals lower IE is because of a lower number of ______ are present in the nucleus on the _____ side of the table when compared with the ______ side.

•therefore, there is ______ in the nucleus to ____ those electrons in towards the nucleus, and they are more easily ______for elements on the _____ side of the table.

•down a group, IE will tend to ______.

•just as ______ was affected by the electrons being added to s and p orbitals that were farther and farther away from the ______, IE is affected in the same way, leading to an ______removal for electrons that lie in the ______, most______s and p orbitals.

•also, you must realize that electrons that lie ______ the nucleus and those outermost s and p electrons will tend to ______the ______of the ______ from those outermost electrons.

•thus, the overall trend line for IE looks like the figure to the right.

•the placement of the arrowhead in the ______corner of the table indicates that you will find the elements with the ______IE there.

•note that ______ is the element that has the ______IE (other than the ______).

3. Ionic Radii

•ionic radii (____ size) is the ____ size of an atom after it has either ______or _____ one or more ______, forming an _____.

•there are two kinds of ions: ______and ______.

•______ions are known ascations.

•the formation of a cation (by the _____ of one or more electrons) always leads to a ______ in atomic radius because the ______of the ______-______-______electrons results in a ______electron cloud.

•also, the remaining electrons are drawn ______to the nucleus by its ______positive charge.

•negative ions are known as______.

•the formation of an anion (by the ______of one or more electrons) always leads to an ______ in atomic radius.

•this is because the ______of the nucleus remains ______ when an electron is ______to an atom or an ion.

•so the electrons are ____ drawn to the nucleus as ______as they were ______ the addition of the extra electron.

•the electron cloud also ______because of greater ______between the increased number of ______.

•within each period of the periodic table, the ______at the _____ tend to form ______and the nonmetals at the ______tend to form anions.

•cationic radii ______ across a period because the electron cloud ______due to the increasing ______charge acting on the electrons in the same main energy level.

•anionic radii ______ across each period for the elements in the upper p-block. The reasons for this trend are the ____ as the reasons that cationic radii decrease from left to right.

•as they are in ______, the outer electrons in both cations and anions are in ______energy levels as one reads down a ______.

•therefore, just as there is a ______of atomic radii down a group, there is also a gradual increase of ______radii.

•thus, the overall trend line for ionic radii looks like the figure to the right.

•the placement of the ____arrowhead in the ______corner of the table indicates that you will find the elements with the ______ionic radii there.

•note that ______ is an element with a very _____anionic radii. Aluminum is an element with a very small ______ radii.

4. Electronegativity

•electronegativity is a measure of the ______of an atom in a chemical compound to ______electrons.

•remember that ______electrons are the only electrons involved in ______.

•some elements are ______able than others to ______the valence electrons involved in the bonding process.

•an ______concentration of charge in a compound affects the ______ of that compound.

•if electrons within a compound are being pulled ______ in one direction, the molecule is said to be “______” or “______” (depending on what ______ are involved).

•if there is an ______ distribution of electrons, and thus, charge, on a molecule, then it is said to be “____-______.”

•Linus Pauling, one of America’s greatest chemical minds, created an ______ to relate elements to each other.

•he assigned ______, the most electronegative element, a value of _____.

•values were assigned to all the other elements ______ to this value.

•across a period, electronegativity values ______ from left to right., and down a ______, they tend to ______.

•thus the trend line for electronegativity looks like the figure to the right.

•the placement of the arrowhead in the ______corner of the table indicates that you will find the elements with the ______ electronegativities there.

•notice ______ is the element with the most electronegativity.