Chemistry H - Unit 9: Periodicity

Which element has a greater ionization energy? *Sodium or Argon*

Argon

The distance from the center of the nucleus to the outer edge of the electron cloud.

Atomic Radius - Decrease in going from left to right across a period

As protons are added one by one to the nucleus to build up the elements, electrons are similarly added to these hydrogen-like orbitals.

Aufbau Principle

Which element has a greater atomic size? *Carbon or Boron*

Boron

Which element has a greater ionization energy? *Lithium or Boron*

Boron

The attraction between charged species is related to the magnitude of their changes.

Coulomb's Law

Arrange the elements in order of increasing ionization energy: *Bi, Cs, Ba*

Cs, Ba, Bi

The ability of an atom to pull the shared electron cloud with another atom within a bond toward itself.

Electronegativity

Explain why fluorine has a smaller atomic radius than oxygen.

Fluorine has a greater nuclear charge than oxygen.

Explain why fluorine has a smaller atomic radius than chlorine.

Fluorine has one less than Chlorine.

What is the energy required to remove an electron from a gaseous atom?

Ionization Energy

Which element has a greater ionization energy? *Cesium or Lead*

Lead

Which element has a greater atomic size? *Silicon or Magnesium*

Magnesium

Which element has a greater ionization energy? *Magnesium or Strontium*

Magnesium

It always requires ____________ to remove a second electron

More Energy

Arrange the elements in order of increasing ionization energy: *Na, Al, S*

Na, Al, S

When the elements are arranged in the periodic table in order of ascending atomic number, a regular change in the outermost electronic configuration is observed.

Periodicity

What is the energy required to remove a second electron from an atom?

Second Ionization Energy

Which element has a greater atomic size? *Selenium or Oxygen*

Selenium

Which element has a greater atomic size? *Sodium or Lithium*

Sodium

Arrange these elements in order of decreasing atomic size: *Sulfur, Chlorine, Aluminum, and Sodium*

Sodium, Aluminum, Sulfur, Chlorine

Arrange the elements in order of increasing ionization energy: *Sr, Be, Mg*

Sr, Mg, Be

Why is there a very large increase between the 1st and 2nd ionization energies for the elements in group 1?

The second electron is being removed from an element that is isoelectronic with a noble gas.

What kind of charge does an atom have after an electron is removed?

a positive charge

As you move from left to right across a period on the periodic table the size of an atom will ________.

decrease - This happens because as you move across a period each element has one more proton in its nucleus than the last one.

The ionization energy of the elements will ___________ as you move down a group on the periodic table.

decrease - This is because the electrons are less attracted to the nucleus as they get further away from the nucleus.

Within a period the elements will have the same number of occupied ___________.

energy levels

As you move from top to bottom down a group on the periodic table the size of an atom will _________.

increase - This happens because as you move down the group each element has one more occupied energy level than the last one

The ionization energy of the elements will ___________ as you move from left to right across a period on the periodic table.

increase - This is because the electrons are all the same distance from the nucleus in the same period, but the elements have more protons as you move from left to right across the periodic table.

Electrons which are further from the nucleus are _______ attracted to the nucleus because of this effect.

less

The energy required to remove an electron is always much, much greater if the atom is isoelectronic with a ___________ before the electron is removed.

noble gas

The ___________ effect is cause by inner electrons interfering with the attraction of outer electrons for the protons in the nucleus.

shielding

The decrease in atomic size as you move from left to right across the periodic table becomes less pronounced as you move ______ the periodic table.

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