9 -- Part 1: The Periodic Table and Some Atomic Properties
The form of the periodic table was established by 9 sizes of atoms.
Discuss the relative tendencies of metals, nonmetals, and metalloids in terms of their ground-state electron configurations.
A period and down a group, and interpret the trends in terms of effective nuclear charge.
Determine if the neutral atom from which the ion is derived is larger or smaller than the ion.
Explain the variation of energy between periods and groups.
Explain the variation of electron affinity across a group.
There is a relationship between polarizability and atomic volume.
The iron atoms were adsorbed onto a surface of the variation of polarizability across the copper atoms.
The iron atoms were moved down a group.
The colors are from a computer rendering.
The periodic table is discussed in this chapter.
Even though there are aspects of the periodic table that we don't fully understand, we continue to use it.
About 50 years after the table was created, our understanding of the rationale behind it took a huge leap forward because of the insights provided by quantum mechanics.
The periodic table is based on the electron configurations of the Ele ments.
In this chapter, we will use the table as a backdrop for a discussion of some elements, including atomic radii, electron affinities, and polarizabilities.
The periodic table is an indispensable guide throughout the rest of the text, as the atomic properties arise in the discussion of chemical bonding in the following two chapters.
The elements are arranged in a way that increases their atomic mass.
The periodic law was based on the property called atomic volume, which is the atomic mass of an element divided by the density of its solid form.
The graph of atomic volume against atomic mass was presented by Meyer.
There are high atomic volumes for the alkali metals Li, Na, K, Rb, and Cs.
Hardness, compressibility, and boiling points are some of the physical properties of the elements examined by Meyer.
The periodic table is a tabular arrangement of elements that are similar.
Meyer's work attracted more attention because he left blank spaces in his table for undiscovered elements, and he corrected some atomic mass values.
The elements we now know as technetium, germanium, and Scandium were all found in his table.
He corrected the atomic mass values of indium and uranium.
The English translation of Moderen Therien was written by Meyer.
There are peaks at the alkali metals in the graph.
The volume of a mole of atoms is not the same as the volume of a gas's molar volume.
The discovery of the periodic table came from his attempts to systematize properties of the elements for presentation in a chemistry textbook.
After his death, his book went through five more editions.
The elements were arranged into eight groups and twelve rows.
The formulas were written by Mendeleev.
R2O, RO, and so on are formulas of the element oxides, as well as formulas of the element hydrides, such as Stamp from the private collection of Professor C. M.
Similar elements fall in vertical groups, and the prop alkali metals are discussed in erties of the elements change from top to bottom in the group.
The order Li 1174 degC2 7 Na 197.8 degC2 7 K 163.7 degC2 7 Rb 138.9 degC2 7 Cs 128.5 degC2 has low melting points.
The discovery of new elements was made after the appearance of the 1871 periodic table.
The table shows how close the predictions for eka-silicon are to the germanium discovered in 1886.
The success of Mendeleev's predictions stimulated chemists to adopt his table fairly quickly, despite the fact that new ideas in science take hold slowly.
The noble gases were one of the elements that Mendeleev did not anticipate.
He did not leave any blanks for them.
They were put in a separate group of the table.
The first noble gas discovered in the 19th century, argon, had an atomic mass greater than that of chlorine, so it was placed between the halogen elements and the alkali metals.
The basis for the periodic law was based on the Atomic Number, which placed elements out of the order of increasing atomic mass to get them into the proper groups.
He thought it was because of the atomic mass errors.
The out-of-order placements were justified by chemical evidence.
Elements were placed in groups based on their chemical behavior.
There was no explanation for the reordering.
The research done by Henry G. J. Moseley on the X-ray spectrum of the elements changed things in 1913.
The following is how X-ray emission can be explained.
The difference in energy between the originating level and the vacancies careers were launched by the brilliant scientists who were down to fill the vacancies.
The energy required to remove an electron Ernest Rutherford was the reason given by Moseley.
The frequencies of emitted X-rays should be killed by the nuclear charges of the atoms in the target.
The father-son team of W. Henry Bragg and World War I developed techniques for fighting in Turkey.
Bragg obtained photographic images of the X-ray spectrum and assigned frequencies to the lines.
The frequencies of X-ray were correlated with the positions of elements in the periodic table.
The three new elements were discovered in 1937, 1945, and 1925.
There could not be any new elements beyond those three in the portion of the periodic table he worked.
There were all available atomic numbers.
The periodic law should be restated from the standpoint of Moseley's work.
There are similar properties when elements are arranged.
The Long Form Mendeleev's periodic table had 8 groups, but most modern periodic tables are arranged in 18 groups of elements.
The periodic table is described in Section 2-6.
The electrons collide with the metal target.
The metal atoms of the target have their electrons ionized by the highly energetic electrons.
electrons from higher orbitals drop down to occupy the vacancies and emit X-ray photons that correspond to the energy difference between the two orbitals The direction of increasing X-ray Frequency in these experiments is caused by the displacement of the lines to the left with each successive element.
The sample contained one or more other elements if more than two lines appeared.
One line in the Co spectrum matches a line in the Fe spectrum, and another line in the Ni spectrum.
There are two lines for Cu and two for Zn in brass.
The elements in the periodic table are brought together by vertical groups.
The horizontal periods of the table are arranged in a way that increases the atomic number from left to right.
The groups are numbered from top to bottom.
Most metals are good conductors of heat and electricity and have moderate to high melting points.
Nonmetals are nonconductors of heat and electricity and are nonmalleable, but a number of nonmetals are gases at room temperature.
Most of the elements in the periodic table aretan and nonmetals are confined to the right side of the table.
The noble gases are treated as nonmetals.
Several elements near a stairstep diagonal line are often called metalloids.
One of many different electron configurations of the atom's constituent atoms may be related to similarities in the principle of the atom's structure.
In Let's now briefly explore a few of the links between the electron configura most contexts, the electron tions of atoms and some observations about the elements, starting with the configuration of an atom usu noble gases.
In the lowest energy state of noble gases, the maximum num atoms are usually in the ber of electrons allowed in the valence shell.
The electron configurations seem to confer a high degree of chemical inert Compounds to the noble gases.
The elec has been prepared with the help of block metals, radon, xenon, and krypton together with Al.
Nonmetals gain compounds with enough electrons to achieve the same configurations.
Other electron configurations give the energy required to bring about ionising.
A noble gas electron configuration is formed by block metal.
To get the electron configuration of the previous noble gas, 10 d electrons would have to be removed from the block elements.
Table 9.2 summarizes the block metal ion.
The atoms of groups 17 and 16 have less electrons than the noble gas at the end of the period.
The metal ion is printed in black and blue.
The outermost shell of the ion contains 18 electrons and is called the next-to-outermost electron shell.
The necessary energy can be supplied by other processes that occur at the same time.
A nonmetal ion with a charge of -2 is rare.
The noble-gas contained in the nitride ion, N3-, and some metal phosphide have electron configurations.
When a transition metal atom ionizes, electrons from the ns orbital are taken out first.
A useful mnemonic is that transition metal ion with charges of +2 or higher have all their electrons in the (n - 1) d orbitals.
Sc in Sc3+ and Ti in Ti4+ have noble-gas electron configurations when forming cations, but most transition metal atoms do not.
13Ar43d62 + 2 e does not form the ion Fe3+ if an additional 3d electron is lost.
Hydrogen does not fit in the periodic table.
Even though hydrogen is a nonmetal, it is often placed in group 1 because the ground-state electron configuration of the H atom resembles that of the group 1 metals.
When hydrogen is subjected to pressures of 2 million bar, it becomes metallic, but these are not ordinary laboratory conditions.
Hydrogen is sometimes placed in group 17 because it is one electron short of a noble-gas electron configuration.
H2 is a reducing agent, while F2 and Cl2 are excellent oxidizing agents.
The importance of atomic mass was discovered in earlier chapters.
We need to know about atomic sizes to understand physical and chemical properties.
The first of a group of atomic properties that we will examine in this chapter is atomic radius.
It's difficult to define the atomic radius.
We have seen that atomic orbitals extend.
There is always a chance of finding an electron at a large distance from the nucleus.
An atom doesn't have a precise outer boundary.
We can't make a measurement of the radius of a single atom.
A measure of the size of an atom can be obtained when it is combined with other atoms.
In terms of internuclear distance, atomic radius is defined.
The distance between the nuclei of two atoms is the basis for the atomic radius.
The distance between the cation and anion must be apportioned because they are not the same size.
If you want to apportion the electron density between the ion, you need to know the radius of the other ion.
O2 is an ionic radius of 140 pm.
An alternative method of apportioning is to use F-.
Carefully note which convention is used when using ionic radii data.
The values of the atomic radii of noble gases are the subject of a lot of debate.