Group , periodic numbering

Periodic table. The group numbers stand above the columns. The numbers at the left of the rows are the period numbers. The black line separates the metals from the nonmetals. [Note A complete periodic table is given inside the front cover.)... 

The periods and the groups are identified differently. The periods are labeled from 1 to 7. Some reference is made to period numbers. The groups are referred to extensively by number. Unfortu-... 

Make a rough sketch of the periodic table for elements 1 through 18, including the following information group number, period number, atomic number, atomic symbol, and condensed electron configuration. 

Patterns Involving Group Numbers and Period Numbers... 

You do not have a periodic table. You are told that the condensed electron configuration for strontium is [Kr]5s. Identify the group number, period number, and orbital block in which strontium appears on the periodic table. Show your reasoning. 

From the electron configuration, you can deduce the energy level of the valence electrons, which tells you the period number for strontium. The number of valence electrons and their sublevel enable you to deduce the group number and the block. Therefore ... 

All elements in group 2 (IIA) have electron configurations that end with the notation s. The link between n value and period number is correctly applied. Strontium has an electron configuration with the general notation ns, which is characteristic of s block elements. 

Table 1.1 An arrangement showing the relationship between the atomic orbitals filled and the number of elements in the various groups and periods of the Periodic Table. Both the major blocks mimic the arrangement of the elements in the 18-group Periodic Table ...

The valence electron configuration of the atoms of the Group 2 elements is ms2, where n is the period number. The second ionization energy is low enough to be recovered from the increased lattice enthalpy (Fig. 14.22). Hence, the Group 2 elements occur with an oxidation number of +2, as the cation M2+, in all their compounds (Table 14.7). Apart from a tendency toward nonmetallic character in beryllium, the elements have all the chemical characteristics of metals, such as having basic oxides and hydroxides. 

In order to find the group and period number of any atom, the ground state electron configuration is written first. Then the following points are taken into consideration. 

The electron configuration of 58Ce is [Xe]6s2 4f2. What are the group and period numbers of 58Ce ... 

Since the number of shells increases in the same group from top to bottom (by the period number increases), the atomic radius also increases. This means that the electron cloud around the nucleus becomes larger. The increase in the number of electrons causes them occupy a new energy level and orbitals. A higher energy level is always further from nucleus. Within a period, if the number of protons and electrons increases, the nuclear attraction force increases. This attraction force prevents an enormous increase in atomic radius. Atomic Radius Within a Period... 

The elements in a column are known as a group, and groups are numbered from 1 to 18. Older numbering styles used roman numerals and letters. A row of the periodic table is known as a period, and periods of the known elements are numbered from 1 to 7. The lanthanoids are all in period 6, and the actinoids are all in period 7. 

The most metallic element is francium at the bottom left of the table. The most nonmetallic element is fluorine. The metallic character of elements within a group increases with period number. This means that within a column, the more metallic elements are at the bottom. The metallic character of elements within a period decreases with the increase in group number. This means that within a row, the more metallic elements are on the left. 

To compare the size of an atom, we need to compare radii among different atoms using some standard. As seen to the right, the sizes of atoms decrease with period number and increase with group number. This trend is similar to the trend described above for metallic character. The smallest atom is helium. 

The known densities of liquid and solid elements at room temperature are shown to the right. Intermolecular forces contribute to density by bringing nuclei closer to each other, so the periodicity is similar to trends for melting point. These group-to-group differences are superimposed on a general trend for density to increase with period number because heavier nuclei make the material denser. 

A summary table should be prepared for each period in which a death or sacrifice occurred, and for each dose group the number dying, the number sacrificed, the number of animals necropsied completely, and the number necropsied to any extent. This section should also include a summary table of tumor occurrences with deaths and sacrifices combined, organized by body system, organ, tumor type, and dose level. The number of animals with tumors of the stated type should also be included. 

Groupings of numbers and decimal points. The common U S. practice of using commas to separate multiples of 1000 is not followed with SI which uses a space instead of a comma to separate the multiples of 1000. For decimals, the space is filled on both sides of the decimal point. The decimal point is placed on the line as a regular period for U.S. usage rather than at mid-line height or use of a comma as is frequent European practice. When writing numbers with values less than one, a zero should be placed ahead of the decimal. 

Figure 2.3 Eight-group periodic table of the 81 stable elements, in spiral form available sites on the prime-number cross, starting from zero, number...

State the group number and period number of each of the following elements ... 

---