Atomic Radius Lesson

Atomic Radius

Atomic radius is the distance from the atom's nucleus to the outer edge of the electron cloud. This shows us the size of the atom.

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Radius of an Atom

What are the sizes of the atoms on the periodic table?

The Periodic Table is separated into GROUPS and PERIODS

Groups are vertical Columns on the Periodic Table. They run from top to bottom (Longways)

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GROUPS

Groupss are labeled on the top of your reference tables (Groups 1 - 18).

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GROUPSS

The group number tell you the number of valence electrons

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Elements in the same group or column has simlar properties

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Periods are horizontal rows on the periodic Table. They run from left to right (across)

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PERIODS

Periods are labeled on the sides of your reference tables (Periods 1 - 7).

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PERIODS

The PERIOD NUMBER tells you the number of energy levels

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Multiple Choice

UP and DOWN columns on the periodic table are

• Periods

• Groups

Multiple Choice

Left to right rows on a periodic table are

• Groups

• Periods

Multiple Choice

Which elements have properties in common?

• Elements in groups

• Elements in periods

Multiple Choice

The group numbers tells us the number of

• Periods

• energy levels

• valence electrons

Multiple Choice

The period number tells you the number of

• protons

• valence electrons

• energy levels

Multiple Choice

Which two elements have properties in common?

• Nitrogen and Phosphorous

• Sulfur and Nitrogen

• Oxygen and Nitrogen

Multiple Choice

Do these elements have properties in common?

• Yes

• No

Multiple Choice

These elements are in a:

• Group

• Period

Multiple Choice

Do these elements have properties in common?

• Yes

• No

Multiple Choice

These elements are in a

• Group

• Period

How does atomic radius change throughout the periodic table?

The Atomic Radius increases down a group and decreases accross a period

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Atomic Radius on the Periodic Table

​Take a close look at how the atomic radius changes across a period and down a group

We add an energy level as move down a group. The atom gets larger

We add more protons to the nucleus as we move across a period. A bigger positive pull from the nucleus makes the atom tighter and smaller

Moving down group 2 - atoms get bigger
A28Moving down group 2 - atoms get biggerAlways count energy levels to see which atom is bigger

lways count energy levels to see which atom is bigger

Use pages 10 -11 to find the radius of the atom and compare to see which is bigger or smaller

Multiple Choice

Which atom has the largest atomic radius?

• potassium (K)

• 
  francium (Fr)

• rubidium (Rb)

• cesium (Cs)

Multiple Choice

As you move down the periodic table atoms get bigger.  This is because ____________.

• he atoms have more mass.

• The atoms have more energy levels

• The atoms have more protons.

• he atoms have more nuetrons

Multiple Choice

As you move across the periodic table atoms tend to get smaller because, ______________.

• the atoms have more mass.

• the atoms have more protons.

• the atoms have less mass

• the atoms have less electrons.

Multiple Choice

The atom with the largest atomic radius in Group 18 is -

• Ar

• Kr

• Rn

• He

Multiple Choice

Which of the following will have a larger radius than Zinc? Use Table S

• 
  Gallium

• Magnesium

• Aluminum

• Strontium

Multiple Choice

Which one has the largest radius?

• Lithium (Li, atomic #3)

• Neon (Ne, atomic #10)

• Boron (B, atomic #5)

• Nitrogen (N, atomic #7)

Multiple Choice

Order the following in increasing atomic radii:

Ra, Be, Ca, Rb, H

• Ra, Be, Rb, H, Ca

• Ra, Rb, Ca, Be, H

• Rb, H, Ca, Be, Ra

• H, Be, Ca, Rb, Ra

Multiple Choice

The more protons there are, the ____ .

• Weaker the pull from the nucleus

• Stronger the pull from the nuclus

• Smaller the electrons

• The bigger the electrons