Section 3 Trends and the Periodic Table Chapter 5 Section 3 Trends and the Periodic Table

Valence Electrons ______________: the electrons available to be lost, gained, or shared in the formation of _____________________ Usually, _________energy level Valence electrons are often located in ____________filled main-energy levels Groups 1 and 2 have ________valence electrons, groups 13-18 have _________ __________________________________

ALL Periodic Table Trends Influenced by three factors: 1. _________________ Higher energy levels are further away from the nucleus. ____________________________ 2. ______________________(protons) More charge pulls electrons in closer. (+ and – attract each other)

Shielding The electron on the ________energy level has to “look through” all the other energy levels to see the nucleus. It is “__________”. A different electron has ______shielding, if it is in the __________

What do they influence? ____________and ________ have an effect on the GROUP (  ) ___________has an effect on a PERIOD (  )

______________- Group trends H As we go ______a group). . . each atom has an _________energy level, so the atomic radii (size) _________ Li Na K Rb

_____________- Period Trends Going from left to right across a period, the atomic size ____________. Electrons are in the ________________. But, there is more _______________. Outermost electrons are pulled _________. Na Mg Al Si P S Cl Ar

Rb K Period 2 Na Li Atomic Radius (pm) Kr Ar Ne H 3 10 Atomic Number

Ions Some compounds are composed of particles called “________” An ______is an atom (or group of atoms) that has a ________________________ ________are neutral because the number of protons equals electrons Positive and negative ions are formed when electrons are ____________(lost or gained) between atoms _______and ________are no longer equal

___________________, from their outer energy level Ions ___________________, from their outer energy level Sodium loses one: there are now more protons (11) than electrons (10), and thus a positively charged particle is formed = “___________” The charge is written as a number followed by a plus sign: Na1+ Now named a “_____________”

____________________one or more electrons Ions ____________________one or more electrons Chlorine will gain one ___________ Protons (17) no longer equals the electrons (18), so a charge of -1 Cl1- is re-named a “chloride ion” Negative ions are called “_________”

Trends in Ionic Size: Cations Cations form by ___________electrons. Cations are ________than the ______atom – not only do they lose electrons, they can lose an entire energy level. ________generally form cations. Cations of __________________elements achieve the electron configuration of the noble gas ______________them.

Ionic size: Anions Anions form by __________electrons. Anions are _______than the atom they came from – have the same energy level, but a reduced _______ nuclear charge. ________________form anions. Anions of _______________elements achieve an electron configuration like the ___________that ________them.

Configuration of Ions _______often have noble gas configurations (a _______outer level) Na atom is: ________________ Forms a 1+ sodium ion: ___________ Same configuration as _________.

Size of Isoelectronic ions Iso- means “the ________” Isoelectronic ions have the same # of ______________ Al3+ Mg2+ Na1+ Ne F1- O2- and N3- all have _____electrons all have the same configuration: _________(which is the noble gas: ____)

Driving Forces ________________require lots of energy to remove their ________. _____________have full orbitals. Atoms behave in ways to try and achieve an __________________ that is like a _____________.

Trends in Ionization Energy _________________is the amount of energy required to completely ____________ an electron (from a gaseous atom). Removing one electron makes a 1+ ion. The energy required to remove only the ______outer electron is called the ________________________.

Ionization Energy The ________ionization energy is the energy required to remove the __________electron. Always ___________than first IE. The ______IE is the energy required to remove a ___________electron. _____________than 1st or 2nd IE.

Symbol First Second Third 11810 14840 3569 4619 4577 5301 6045 6276 HHeLiBeBCNO F Ne 1312 2731 520 900 800 1086 1402 1314 1681 2080 5247 7297 1757 2430 2352 2857 3391 3375 3963 Why did these values increase so much?

What factors determine IE The ________the nuclear charge, the ______________IE. _____________distance from nucleus _________________IE Shielding effect = lower IE _______and _________orbitals have ______potential energy, so achieving them is easier. This means _____IE.

Ionization Energy - Group trends As you go _________a group, the first IE ______ because... The electron is ________away from the attraction of the nucleus, and there is more _______________.

Ionization Energy - Period trends All the atoms in the _________period have the ________energy level (Same shielding.) But, ____________nuclear charge So IE generally ____________from left to right. Exceptions at ____and _____orbitals.

First Ionization energy Atomic number

Trends in Electronegativity _______________is the tendency for an atom to __________electrons to itself when it is covalently bonded with another element. They share the electron, but how equally do they share it? An element with a __________ electronegativity means it pulls the electron towards itself ___________.

Electronegativity Group Trend The farther _________a group, the farther the electron is away from the _______. There is also more __________occurring. Attraction for that electron is ______so low _____________. Going ________the group, electronegativity __________.

Electronegativity Period Trend _______are at the _____of the table and they let their electrons go ____ Thus, low _______________ On the ____side are the _________. They want _____electrons and try to take them from other ________. Going __________the period, electronegativity ______________. Think back to _________________.

Trend: ___________(and ionic size) decrease going across the period and increase going down a group:

Trend: ___________________ and _______________increase going across the period and increase going up a group