![]() Consider the following elements:Na, Ca, Al, K, Mg, Li (a) Which of these elements belong to the same period of the periodic table? (b) Which of these elements belong to the same group of the periodic table?.(a) What is the main characteristic of the last elements in the periods of the periodic table? What is the general name of such elements?(b) What is the number of elements in: (a) 1st period, and (b) 3rd period, of the modern periodic table?.Define the Periodic Table with elements name.Atomic number of a few elements are given below 10, 20, 7, 14(a) Identify the elements(b) Identify the Group number of these elements in the Periodic Table(c) Identify the Periods of these elements in the Periodic Table(d) What would be the electronic configuration for each of these elements?(e) Determine the valency of these elements.(a) What is the usual number of valence electrons and valency of group 18 elements of the periodic table?(b) What happens to the number of valence electrons in the atoms of elements as we go down in a group of the periodic table?.(a) How does the electropositive character of elements change on going down in a group of the periodic table?(b) State how the valency of elements varies (i) in a group, and (ii) in a period, of the periodic table.In the modern periodic table, which are the metals among the first ten elements?.Compare and contrast the arrangement of elements in Mendeleev’s Periodic Table and the Modern Periodic Table.What is the major characteristic of the first elements in the periods of the periodic table? What is the general name of such elements?.Name of 118 elements in the periodic table.How does the valency of elements change on moving from left to right in the third period of the periodic table?.How does the valency of elements vary in going down a group of the periodic table?.The distance between the radii is 266 p m. Beneath the molecule is the label, “B r radius equals 228 p m divided by 2 equals 114 pm.” The fourth diatomic molecule is in purple. The distance between the radii is 228 p m. Beneath the molecule is the label, “C l radius equals 198 p m divided by 2 equals 99 pm.” The third diatomic molecule is in red. The distance between the radii is 198 p m. The second diatomic molecule is in a darker shade of green. Beneath the molecule is the label, “F radius equals 128 p m divided by 2 equals 64 p m.” The next three models are similarly used to show the atomic radii of additional atoms. The distance between the centers of the two atoms is indicated above the diagram with a double headed arrow labeled, “128 p m.” The endpoints of this arrow connect to line segments that extend to the atomic radii below. Two spheres are pushed very tightly together. The first model, in light green, is used to find the F atom radius. ![]() In figure a, 4 diatomic molecules are shown to illustrate the method of determining the atomic radius of an atom. The general trend is that radii increase down a group and decrease across a period. ![]() (b) Covalent radii of the elements are shown to scale. The atomic radius for the halogens increases down the group as n increases. \): (a) The radius of an atom is defined as one-half the distance between the nuclei in a molecule consisting of two identical atoms joined by a covalent bond. ![]()
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