The Atomic Structure

עמוד:13

Electrical forces of attraction and repulsion 13 When we comb our hair on dry days , the hair gets attracted to the comb and stands on end . Why ? This phenomenon is a result of the force of the electrical attraction between the comb and the hair . When the hair is combed , the comb becomes charged with a negative electrical charge , whereas the hair gets charged with a positive electrical charge . Bodies with opposite electrical charges are attracted to one another , and therefore the invidual hairs repel one another and the comb are attracted to each other . On the other hand , forces of repulsion act on bodies with the same electrical charge and therefore the individual hairs repel one another . Bodies charged with a positive electrical charge will repel each other , and the same applies to bodies charged with a negative electrical charge . These forces , attraction and repulsion , between electrically charged bodies , are known as electrical forces ( electrostatic )* . This can be summarized in the diagram on the right . Question Answer the following questions according to what you have read about the electrical charges of the components of the atom and about the forces of attraction and repulsion between electrical charges . A . Which forces are in action between the protons and the electrons ? Explain . B . Which forces are in action between the protons and other protons ? Explain . C . Which forces are in action between the electrons and other electrons ? Explain . The atom is mostly empty space . At the center of the atom lies a tiny nucleus with electrons around it in a kind of “ cloud” . The atom's nucleus is made up of two kinds of particles – protons and neutrons . The nucleus has a positive electrical charge , which is a result of the charge on the protons . The electrons have a negative electrical charge . The mass of the electrons is very small relative to the mass of the protons and neutrons , and therefore most of the atomic mass is concentrated in the nucleus . Electrical forces of attraction and repulsion act among the components of the atom ( electrostatic forces ) : the positively charged protons within the nucleus attract the negatively charged electrons orbiting it . The forces acting between the protons themselves and the electrons themselves are repulsive forces . Electrical forces – ( electrostatic ) forces of attraction and repulsion , acting between electrical charges . Electrical charges with opposite symbols attract each other , whereas electrical charges with the same symbols repel each other . Electrical charges with the same symbols repel each other . Electrical charges with opposite symbols attract each other .

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