Have each member of your group sketch a periodic table...

Name: Problem 132, Chapter 9: Chemistry A Molecular Approach
Uploaded: 2019-06-25T15:48:29-08:00
Duration: 6 min 54 s
Channel: Lyniesha Wright
Description: Have each member of your group sketch a periodic table indicating a periodic trend (atomic size, first ionization energy, metallic character, etc.). Have each member present his or her table to the rest of the group and explain the trend based on concepts such as orbital size or effective nuclear charge.

Have each member of your group sketch a periodic table indicating a periodic trend (atomic size, first ionization energy, metallic character, etc.). Have each member present his or her table to the rest of the group and explain the trend based on concepts such as orbital size or effective nuclear charge.

Key Concepts

Periodic Trends

Periodic trends are the systematic variations in the physical and chemical properties of elements as you move across periods or down groups in the periodic table. These trends, such as changes in atomic radius, ionization energy, and metallic character, emerge due to the arrangement of electrons in atomic orbitals and the influence of effective nuclear charge. They help explain why elements behave similarly within the same group and differently across a period.

Effective Nuclear Charge

Effective nuclear charge is the net positive charge experienced by an electron in an atom, calculated by subtracting the shielding effect of the inner electrons from the total nuclear charge. This concept is crucial in explaining trends in atomic properties; as the effective nuclear charge increases, electrons are drawn closer to the nucleus, resulting in smaller atomic radii and generally higher ionization energies.

Orbital Size

Orbital size refers to the spatial extent or volume of the region in an atom where there is a high probability of finding an electron. It plays a significant role in determining atomic properties as larger orbitals can result in a more diffuse electron cloud, affecting the atom's size and how strongly the electrons are held by the nucleus.

Transcript

00:01 First ionization energy and metallic character.

00:05 And then to have each member present his or her table to the rise of the group and explain the trend based on the concepts such as orbital size or effective nuclear charge.

00:14 So we only have one person.

00:21 So i'm going to do all of those trends and i'm going to do them on the same periodic table.

00:31 We're going to pretend that these lines are straight.

00:35 We're not going to include the f block in this analysis and it's supposed to do them.

00:38 That the trend is going to proceed in the same manner.

00:41 So the first concept we're going to look at is atomic size.

00:44 We're going to do atomic size in red.

00:51 As you go across the table from left to right, the atomic size decreases.

00:57 So i'm going to write the word decrease.

01:10 All right.

01:11 So we go from left to right, the atomic size decreases.

01:14 And as we go down the periodic table, the atomic size increases.

01:27 And we're going to look at this based on the concept of effective nuclear charge.

01:33 As you go across the table, the effective nuclear charge increases.

01:38 So the protons in the center have a more positive charge.

01:41 The electrons in the outside are therefore, since they're all in the same energy level, more attracted to that net positive charge.

01:47 Causing that greater attraction, the size of the atom is going to be smaller.

01:51 But as you go down, yes, the effective nuclear charge increases, but there's additional outer orbital or outer energy level.

02:00 So that makes the size of the atom increase.

02:04 Every time you go down a group on the periodic table.

02:08 So as you go across, it decreases, and as we go down, it increases.

02:12 Now let's do first ionization energy in green...

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