Chapter 2.2, Problem 3CC

Summary Introduction

To determine: The number of electrons in a fluorine atom.

Concept introduction: The atomic number of an element is the number of protons in the nucleus of its atoms. In a neutral atom, the number of protons and electrons is equal. Thus, the number of electrons present in a neutral atom is equal to its atomic number.

Summary Introduction

To determine:  The number of shells in a fluorine atom.

Concept introduction: The electrons in an atom present around the nucleus are in constant motion. An electronic shell represents the energy levels and the average distance at which electrons orbit around the nucleus. Simplified diagrams of atoms show the electrons arranged in electronic shells as concentric rings around the nucleus. In an atom, the first shell can contain only two electrons, whereas the second shell can have a total of 8 electrons.

Summary Introduction

To list: The names of orbitals occupied by electrons in a fluorine atom.

Concept introduction: Electronic shells can be subdivided into electronic orbitals. Each electronic orbital represents the three-dimensional volume around the nucleus where an electron is most likely to occur while orbiting around the nucleus. Each orbital can have two electrons. Thus, the number of electrons present in each shell depends on the number of orbitals in each shell. In an atom, the first shell has one orbital called 1s, thus it can contain only two electrons. The second shell has one spherical orbital called 2s, and three dumbbell shaped orbitals named 2p orbitals (Fig. 2). Thus, the second shell can have a total of 8 electrons.

Summary Introduction

To determine: The number of electrons needed to completely fill the valence shell of a fluorine atom.

Concept introduction: The outermost shell of an atom is called the valence shell, and the electrons present in it are called valence electrons.