atomic concepts.....aim 4

what are the valence electrons?

.....aim 3

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HW From textbook “CHEMISTRY a Contemporary Approach”

 

The valence electrons are located in the last energy level of an electron configuration. They are the outermost electrons.

Example

 

       

Problems

What are the valence electrons of elements in group 1,2,13-18? What do you notice?

 

Valence e- can be represented with the electron-dot (Lewis) structure where each electron is represented by a dot around the element.

Example

                              

Problems

Pick 10 elements from groups 1, 2, 13-18 in the periodic table of elements and draw the valence e- for each using the electron-dot structure.

 

In general, the number of valence electrons affects the chemical properties of an element because being on the outermost fringes of an atom they are the one in contact with the world.

 

TEST YOUR UNDERSTANDING

1/07

6 An atom of argon rarely bonds to an atom of another element because an argon atom has

        (1) 8 valence electrons     (2) 2 electrons in the first shell     (3) 3 electron shells     (4) 22 neutrons

1/06

53 In the space in your answer booklet, draw a Lewis electron-dot diagram of a selenium atom in the ground state.

8/06

51 In the space in your answer booklet, draw a Lewis electron-dot diagram for a sulfur atom in the ground state.

52 Explain, in terms of electron configuration, why selenium and sulfur have similar chemical properties.

1/04

62 Draw a Lewis electron-dot structure for an atom of phosphorus.

8/04

32 Which set of symbols represents atoms with valence electrons in the same electron shell?

                (1) Ba, Br, Bi (2) Sr, Sn, I (3) O, S, Te (4) Mn, Hg, Cu

8/03

3 What is the total number of valence electrons in an atom of sulfur in the ground state? (1) 6 (2) 8 (3) 3 (4) 4

12 Which Lewis electron-dot structure is drawn correctly for the atom it represents?

6/02

1  Draw the electron-dot (Lewis) structure of an atom of calcium.

2 Draw the electron-dot (Lewis) structure of an atom of chlorine. 

3  In which shell are the valence electrons of the elements in Period 2 found?  (1) 1         (2) 2           (3) 3      (4) 4

8/02

What is the total number of electrons in the valence shell of an atom of aluminum in the ground state? (1) 8 (2) 2  (3) 3  (4) 10

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