How many sublevels are in the first energy level

Let's revisit orbitals and basic atomic theory. What are they and how do they work with respect to bonding? Below is a diagram that shows the probability of finding an electron around the nucleus of a hydrogen atom.

Notice that the 1s orbital has the highest probability. Since it is very difficult to show these spheres, the energy levels are typically shown in 2 dimensions. Read more about energy level models in the teacher background section.

Tell students that this energy level model represents an atom. The nucleus is represented by a dot in the center, which contains both protons and neutrons. The smaller dots surrounding the nucleus represent electrons in the energy levels. Let students know that they will learn more about electrons and energy levels later in this lesson. Have students look at the Periodic table of the elements 1—20 they used in lesson 2 to answer the following question:.

Show students that you have 80 cards 4 for each of the first 20 elements. Before distributing the cards, explain that each card contains information about electrons and energy levels for the first 20 elements of the periodic table. Remind students that they will need to count the electrons in order to identify each atom. Once students understand what their assignment is, distribute the cards to groups.

After all cards have been placed at the 20 different atoms, select two or three atoms and review whether the cards were placed correctly. This review will help reinforce the concepts about the structure of atoms and help students determine the number of protons and electrons in each atom.

Give each student a Periodic Table of Energy Levels activity sheet. This table contains energy level models for the first 20 elements. The electrons are included only for the atoms at the beginning and end of each period. Project the image Periodic table of energy levels. The image you project contains all of the electrons for elements 1— However, the periodic table on the activity sheet contains electrons only for the elements at the beginning and end of each period.

Discuss the arrangement of electrons within the energy levels for these atoms and have students fill in the electrons for the other atoms. Note : In the energy level diagrams, the electrons are spread out evenly in the level. Some books show them spread out this way and some show them in pairs. The pairing of electrons is meant to represent that electrons are in separate orbitals within each energy level. At the middle school level, it is not necessary for students to learn about electron orbitals.

This information is offered so that it is clearer to you why electrons are often shown in pairs in energy level diagrams and in the dot diagrams used as an extension at the end of this chapter. An orbital defines a region within an energy level where there is a high probability of finding a pair of electrons. There can be a maximum of two electrons in each orbital. This is why the electrons are often shown in pairs within an energy level.

Note : Students may wonder why an energy level can hold only a certain number of electrons. The answer to this is far beyond the scope of a middle school chemistry unit. It involves thinking of electrons as 3-dimensional waves and how they would interact with each other and the nucleus. Continue to project the image Periodic table of energy levels for elements 1—20 and have students look at their activity sheets to find patterns in the number of electrons within each energy level.

The length of each period is determined by the number of electrons that are capable of occupying the sublevels that fill during that period, as seen in the Table 1. Recall that the four different sublevels each consist of a different number of orbitals. The s sublevel has one orbital, the p sublevel has three orbitals, the d sublevel has five orbitals, and the f sublevel has seven orbitals.

In the first period, only the 1 s sublevel is being filled. Since all orbitals can hold two electrons, the entire first period consists of just two elements. In the second period, the 2 s sublevel, with two electrons, and the 2 p sublevel with six electrons, are being filled. Consequently, the second period contains eight elements. The third period is similar to the second, filling the 3 s and 3 p sublevels. Notice that the 3 d sublevel does not actually fill until after the 4 s sublevel.

This results in the fourth period containing 18 elements due to the additional 10 electrons that are contributed by the d sublevel. The fifth period is similar to the fourth. After the 6 s sublevel fills, the 4 f sublevel with its 14 electrons fills.

This is followed by the 5 d and the 6 p. The total number of elements in the sixth period is The later elements in the seventh period are still being created. How does silver become more stable? Review What is the Aufbau principle? Which orbital is filled after the 2 p?

Which orbital is filled after 4 s? Which orbital is filled after 6 s? Show References References Gary Minnaert. CK Foundation — Christopher Auyeung.

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