How many valence electrons are in an atom of chlorine?  Alexia

Concept:

The distribution of electrons in different orbitals is called electronic configuration. The electrons filled in the outermost shell or the electrons present in the highest principal energy level are called valence electrons.

The filling of electrons in different energy levels or orbitals is done in accordance to Aufbau principle. It states that electrons are filled in the orbitals in order of increasing energy of the orbitals. The increasing order of energy of the orbitals is as follows: Solution:

Step: 1 The atomic number of chlorine is 17. The number of electrons in chlorine is 17. The electronic configuration of chlorine is as follows:

Step: 2  The highest principal energy level is 3. The electrons present in 3s and 3p orbital are valence electrons. Distribution of electrons in different orbitals in chlorine atom is shown as: Therefore, the number of valence electrons in an atom of chlorine is 7.

Similar problems:

Question:

1. How many valence electrons are in an atom of carbon?

Solution:

Step: 1 The atomic number of carbon is 6. The number of electrons in carbon is 6. The electronic configuration of carbon is as follows: Step: 2  The highest principal energy level is 2. The electrons present in 2s and 2p orbital are valence electrons. Distribution of electrons in different orbitals in carbon atom is shown as: Therefore, the number of valence electrons in an atom of carbon is 4.

Question:

2. How many valence electrons are in an atom of oxygen?

Solution:

Step: 1 The atomic number of oxygen is 8. The number of electrons in oxygen is 8. The electronic configuration of oxygen is as follows: Step: 2  The highest principal energy level is 2. The electrons present in 2s and 2p orbital are valence electrons. Distribution of electrons in different orbitals in oxygen atom is shown as: Therefore, the number of valence electrons in an atom of oxygen is 6.

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Related Questions
2. (11 marks) a) At 400 °C, ammonium iodide decomposes in the following endothermic reaction: NH41(s) + NH3(g) + HI(g) Kp = 0.215 at 400 °C. Write the equilibrium expression for this reaction. 15.0 g of NH4I was placed in an empty 3.0 L flask and heated to 400 °C. What is the partial pressure of NH3 in the flask once the reaction has reached equilibrium? How would the following changes to the equilibrium mixture affect the number of moles of NH3 in the flask and the value of K, once equilibrium is re-established? (Use increase, decrease or stay the same.) Change Effect on moles of NH3 Ke value Increase temperature Increase volume of flask Remove half of HI gas
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