Periodic table effective nuclear charge

PERIODIC TABLE EFFECTIVE NUCLEAR CHARGE (sections 7.1 and 7.2)... 

The decrease in atomic radius moving across the periodic table can be explained in a similar manner. Consider, for example, the third period, where electrons are being added to the third principal energy level. The added electrons should be relatively poor shields for each other because they are all at about the same distance from the nucleus. Only the ten core electrons in inner, filled levels (n = 1, n = 2) are expected to shield the outer electrons from the nucleus. This means that the charge felt by an outer electron, called the effective nuclear charge, should increase steadily with atomic number as we move across the period. As effective nuclear charge increases, the outermost electrons are pulled in more tightly, and atomic radius decreases. 

Sodium is in Group 1 of the periodic table and can be expected to form a +1 ion. However, the valence electron is tightly held by the effective nuclear charge—... 

Polarizability decreases from left to right in any row of the periodic table. As the effective nuclear charge (Zgff) increases, the nucleus holds the valence electrons more tightly. 

IB From the periodic table inside the front cover, we see that Na is in the same period as A1 (period 3), but in a different group from K, Ca, and Br (period 4), which might predict that Na and A1 are about the same size. However, there is a substantial decrease in size as one moves from left to right in a period due to an increase in effective nuclear charge, enough such that Ca should be about the same size as Na. Table 10-1 shows ... 

How does the effective nuclear charge change among the members of a period on the periodic table ... 

The effective nuclear charge increases towards the right in any period of the periodic table. 

Recall from Chapter 2 that a gradual change in properties as we move in any direction in the periodic table is called a periodic trend. Most periodic trends can be understood from the perspective of the simplified shell model, and underlying most trends are two important concepts inner-shell shielding and effective nuclear charge. 

Was this your answeT Chlorine and oxygen must lie in the same area of the periodic table. Both have strong effective nuclear charges, and both are strong oxidizing agents. 

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