Periodic Trend: Cumulative - Online Tutor, Practice Problems & Exam Prep

Understanding periodic trends is crucial for grasping the behavior of elements within the periodic table. As we consider movement towards the top right corner of the periodic table, we observe two primary types of trends. Metallic character and atomic radius, which we can categorize as Type A trends, tend to decrease. On the other hand, properties that start with 'I' or 'E,' such as ionization energy, electron affinity, electronegativity, and effective nuclear charge, increase and are classified as Type B trends. It's important to note that ionic radius is an exception and does not fit neatly into these categories, as it is influenced by the number of electrons. Remembering these trends can significantly aid in predicting and understanding the chemical properties and reactivity of elements.

Periodic Trend: Cumulative

All right. So now let's do a quick review of all the periodic trends. They can be grouped together. Remember, in all of them, we're moving to the top right corner of the periodic table. And we're willing to say here that some of them can be grouped together.

We're going to call first our periodic trends type A or trend A. This is involving metallic character and atomic radius. As we move to the top right corner for them, we're going to say that they decrease. So type A periodic trends decrease as we head towards the top right corner.

And then here the next one which are type B ones. These periodic trends start with either I or E. So that includes ionization energy, electron affinity, electronegativity, and effective nuclear charge. For them, as we head to the top right corner, they increase.

Now we're going to say since ionic radius depends on the number of electrons, it doesn't belong to either group. So here this is a great way to help you put all your periodic trends on one chart and quickly be able to tell what's happening with each one. So just remember your type A and then your type B periodic trends.

Periodic Trend: Cumulative Example 1

So here it says elements with blank first ionization energies and more blank electron affinities generally form cations. So remember a cation is a positive ion and if you're trying to make a positive ion that means that you're a metal. Remember metals tend to form cations.

Now that we know that it's a metal, let's think about electron affinity and ionization energy for metals. Metals tend to have low first ionization energies. It it's easy to remove their electrons so they can become a positive ion. So here that would mean that the answer is either A or C.

And let's think about electron affinity. Remember, as we head towards the top right corner away from the metals are electron affinity will increase, it becomes more exothermic. So here we're doing the exact opposite. Metals are more to the left, so they're not more exothermic, they're more endothermic. So here we're going to have C as our best answer.

Which of the following statements is false? 

• A. The first ionization energy of chlorine is larger than magnesium.
• B. Anions are larger than their parent atoms.
• C. The removal of the first electron from boron is highly exothermic.
• D. The oxygen atom is smaller than the barium atom.
• E. All of the statements are true.

For main-group elements, the atomic radius increases going down a group because: 

• A. Effective nuclear charge decreases.
• B. The mass of an element increases.
• C. The highest principal quantum number of the valence orbitals increases.
• D. Electron affinity increases.
• E. Both effective nuclear charge and the principal quantum number of valence orbitals increases.

Which of the following statements is false? 

a) The electron affinity of phosphorus is less exothermic than those of both silicon and sulfur. 

b) The second ionization energy of oxygen is less than the first ionization of fluorine.

c) As the principal quantum number of an atom increases the effective nuclear charge will increase. 

d) Cations are smaller than their parent atoms. 

e) The second electron affinity of an atom will be more exothermic than the first electron affinity. 

• A. b only
• B. b and c
• C. a, c and e
• D. a and c
• E. b, c and e

Which of the following statements is true? 

• A. Valence electrons are more difficult to remove than inner core electrons.
• B. Argon and bromide are isoelectronic species.
• C. Francium possesses the greatest electronegativity.
• D. The second ionization energy of an atom is always larger than its first ionization energy.
• E. The aluminum atom will experience a larger jump in its third ionization energy than its fourth.