1) Peut-on situer dans la classification périodique et...

1) Peut-on situer dans la classification périodique et identifier les éléments dont la configuration électronique se termine par le terme indiqué ? Si oui, dans quelle case se trouve-t-il et quel est son nom? a) ...,4s b) ...,5 $\mathrm{p}^6$ c) ..., $7 \mathrm{~s}^1$ d) ..., $3 \mathrm{p}^2$ 2) Peut-on situer et identifier les éléments dont la configuration électronique comporte le terme indiqué, sans que ce soit le dernier? e) $\ldots, 3 d^5, \ldots$ f) $\ldots, 4 p^6, \ldots$ g) $\ldots, 5 \mathrm{~d}^{10}, \ldots$ h) ...,5 $5 \mathrm{f}^2, \ldots$

1) Peut-on situer dans la classification périodique et identifier les éléments dont la configuration électronique se termine par le terme indiqué ? Si oui, dans quelle case se trouve-t-il et quel est son nom?
a) ...,4s
b) ...,5 $\mathrm{p}^6$
c) ..., $7 \mathrm{~s}^1$
d) ..., $3 \mathrm{p}^2$
2) Peut-on situer et identifier les éléments dont la configuration électronique comporte le terme indiqué, sans que ce soit le dernier?
e) $\ldots, 3 d^5, \ldots$
f) $\ldots, 4 p^6, \ldots$
g) $\ldots, 5 \mathrm{~d}^{10}, \ldots$
h) ...,5 $5 \mathrm{f}^2, \ldots$

Key Concepts

Electronic Configuration

Electronic configuration describes the distribution of electrons among the atomic orbitals of an element. It is a fundamental concept in chemistry that explains how electrons are arranged in shells and subshells, influencing the chemical properties and reactivity of the element.

Periodic Table Classification

The periodic table is a systematic arrangement of the chemical elements based on their atomic number and electron configurations. Its structure organizes elements into groups and periods that reflect periodic trends in chemical and physical properties.

Atomic Orbitals and Subshells

Atomic orbitals are regions around the nucleus where electrons are likely to be found. Subshells labeled s, p, d, and f represent different shapes and energy levels of these orbitals. Understanding these subshells is essential for interpreting and writing electronic configurations.

Terminal Electron Configuration

The terminal, or ending, part of an electron configuration specifies the last electrons added to the atom and is crucial in determining the element’s chemical behavior. It indicates which subshell is partially or fully occupied and helps in placing the element within the appropriate block of the periodic table.

Blocks of the Periodic Table

The periodic table is divided into blocks (s, p, d, and f) according to the subshell that is being filled by electrons in the atom’s ground state. Each block groups elements with similar chemical and physical properties, making it easier to identify and compare them based on their electron configurations.

Transcript

00:02 Okay, so here we're going to be looking at groups that follow these general ground state electron configurations.

00:07 So here we have a periodic table and let's just recall that this is the s block here.

00:14 In the center, we have the d block down underneath.

00:20 This is the f block and this gets inserted.

00:22 This block gets inserted here.

00:24 The lanthanites get inserted there and the actinoids get inserted here before the d block.

00:31 And then over here on the right, you have the p block.

00:37 So let's just identify some groups that fit these sort of general ground state configurations.

00:42 So for a, let's write this out.

00:46 So for a, we have ns2 and np4.

00:52 So something that would only have 2 s electrons and 4 p electrons in its valence shell isn't going to have any other electrons, meaning no d electrons or f electrons or anything like that.

01:05 So we're specifically talking about the first three rows here of the periodic table.

01:11 And something that has ns2 and p4, so that's going to have the s1 electron.

01:16 So let me write this here, the s1.

01:19 It will have the s2 electron as well.

01:23 And then it will have four p electrons.

01:25 So this is p1, p2, p3, and p4.

01:34 So those possible species are oxygen or sulfur.

01:39 And that's going to be in group 16.

01:44 So we'll go ahead and assign this group 16.

01:50 And then for b, b is the ns1 group.

01:54 So this is just something that has one s electron only in its valence shell.

02:02 And so that could be anything just with an s1 electron after a complete shell.

02:09 So it could be hydrogen, it would be the easiest one.

02:12 That could also be lithium, sodium, potassium all the way down.

02:15 This group number one is just going to have that one s electron only.

02:20 And it's valent shell.

02:22 So group 1 for this.

02:27 For c, we have ns2, mp6.

02:33 So a species that has its full 1 -2 s -electrons, and then also a full p block, all 6 -p electrons.

02:44 But no d -electrons yet.

02:49 So it's going to have s -1 and s -2 on the left.

02:52 Skip over the d -block, because it's not part of the electron configuration, so we're not down into n -equels 4 quite yet...

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