Chapter 6 The Periodic Table



The Periodic Table-Chapter 6

Organizing the elements

A few elements, such as ______ and ________, have been known for thousands of years.

Yet, only about ___ had been identified by the year 1700.

As more were discovered, chemists realized they needed a way to _____________ the _____________.

Mendeleev’s Periodic Table

Chemists used the ____________ of elements to sort them into __________.

By the mid-1800s, about ______ elements were known to exist

Dmitri Mendeleev – a Russian __________ and ____________ arranged elements in order of ______________ __________ ________.

Thus, the first __________ _________ was created.

Moseley’s Periodic Table

In 1913, Henry Moseley – A British physicist, arranged ___________ according to increasing _________ ___________

This is the arrangement used today

The __________, __________ _________ & _________ are basic items included.

The Periodic Law states:

• When elements are arranged in order of ________________atomic number, there is a periodic ____________of their physical and chemical ___________________.

• Horizontal rows = ____________

o There are ___ _________

• Vertical column = _________ (or __________)

o Similar ___________ & _____________ properties

o Identified by __________ & ________ (IA, IIA)

Areas of the Periodic table

Three classes of elements are: ___________, _____________, and ____________

Metals: electrical conductors, have ________, are __________ and malleable

Nonmetals: generally ________ and dull, poor conductors of heat and electricity.

Metalloids: border the line-2 sides

Properties are intermediate between _____________ and _______________

• Notice the heavy, _________-______ line?

Remember: Many periodic tables are set up differently. Make sure to pay attention!

Electron Configuration in Groups

Elements can be sorted into 4 different groupings based on their ___________ ________________:

1. Representative Elements

2. ____________ __________

3. __________ ________

4. Inner transition metals

1) Representative Elements are in Groups 1A through 7A

• They display wide range of ___________.

• Their outer s and p electron configurations are __________ _________ or already full.

2) Transition metals are in the “B” columns of the periodic table

• A __________ between the _______ area and the ____________ area.

• Electron configuration has the outer s sublevel ______, and is now filling the “d” sublevel.

3) Noble gases are the elements in Group ___ ___ (also called Group 18)

• Previously called “________ _________” because they rarely take part in a reaction; very stable = _______ _______.

• Electron configuration that has the outer s and p sublevels ____________ ___________. The d sub levels may or may not be full.

4) Inner Transition Metals are located below the ______ body of the table, in _____ rows

• Formerly called “______-_______” elements, but this is not always true because some are very abundant.

• Electron configuration has the outer ____ sublevel full. The p and d ___________ may or may not be _______. The ____ ____________ is filling.

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Elements in the 1A-7A groups are called the representative elements

Group 1A are the __________ __________ (but NOT H)

Group 2A are the __________ _________ ____________

Group 8A are the _________ __________

Group 7A are the _________

Trends in Atomic Radius

First problem: Where do you start measuring from?

The __________ ____________ doesn’t have a definite edge.

They get around this by measuring more than 1 atom at a time.

Atomic Size

Measure the Atomic Radius - this is ________ the distance between the _______ nuclei of a diatomic molecule.

Atomic Size- Group Trends

• As we increase the atomic number or go down a group. . .

each atom has another energy level, so the atoms get __________.

Atomic Size-Period Trends

• Going from left to right across a ___________, the size gets __________.

• ____________ are in the same energy level.

• But, there is more nuclear charge.

• Outermost __________ are pulled closer to the atom’s nucleus.

Ions

• An ion is an atom or group of atoms that has a ________ or _________ charge.

• Remember that atoms are neutral because the # of protons = # of electrons.

• Some compounds are composed of particles called ions.

• Positive and negative ions are formed when __________ are __________ (lost or gained) between atoms.

Metals tend to LOSE electrons, from their outer energy level

• Sodium loses one: there are now more protons (11) than electrons (10), and thus a __________ charged particle is formed = “___________”

• The charge is written as a number followed by a plus sign: _________

• Na1+ is re-named a “__________ ________”

Nonmetals tend to GAIN one or more electrons

• Chlorine will gain one _________

• Protons (17) no longer equals the electrons (18), so a charge of 1-

• _______________ ions are called “___________”

• Cl1- is re-named a “chloride ion”

Ionization Energy Trends

________________ energy is the amount of energy required to completely remove an electron (from a gaseous atom).

Removing one ______________ makes a 1+ ion.

The energy required to _________ only the first __________ is called the first ionization energy.

The second ionization energy is the energy required to remove the __________ __________.

Always greater than first IE.

And so on…

Ionization Energy - Group Trends

As you go down a group, the first ionization energy decreases because...

The _____________ is further away from the attraction of the ____________.

Ionization Energy - Period Trends

• All the atoms in the same period have the ________ __________ _________.

• Increasing nuclear charge

• So IE generally _____________from left to right.

• Exceptions at full and 1/2 full ____________.

Driving Forces

Full Energy Levels require lots of energy to ____________ their electrons.

Noble Gases have _______ __________ __________.

Atoms behave in ways to try and achieve a __________ ______ configuration.

Trends in Ionic Size: Cations

• ____________ form by _________ electrons.

• Cations are __________ than the atom they came from – not only do they lose electrons, they lose an ____________ ___________ ____________.

• Metals form _________.

Trends in Ionic size: Anions

• Anions form by _________ electrons.

• Anions are ___________ than the atom they came from – have the same ________ level, but a greater area the nuclear charge needs to cover

• ___________ form _________.

Electronegativity Trends

• _______________________ is the tendency for an atom to __________ electrons to itself when it is chemically combined with another______________.

• They ________ the electron, but how equally do they share it?

• An element with a big electronegativity means it pulls the ______________towards itself _____________!

Electronegativity Trends-Groups

• The further _________ a group, the ____________ the electron is away from the _______________, plus the more electrons an atom has.

• This causes the electronegativity to ____________ as you go down the group.

Electronegativity Trends-Periods

• Metals are on the _______ of the table.

• They let their ____________ go easily

• This causes electronegativity to be on the low side.

• On the ________ are the _______________.

• They want more ____________, so they try to take them away from others

• This causes electronegativity to ____________ as you go across the table.

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