1. Complete the following sentences using words from the list below. equal negative opposite positive zero a) A proton has ………positive…….. charge. b) A neutron has ……zero……….. charge. c) An electron has ………negative…….. charge. d) A proton and an electron have ……opposite……….. and ………equal…….. charge.
2. Complete the following sentences using words from the list below. electron(s) ion(s) neutron(s) nucleus (nuclei) proton(s) a) Every atom contains a ……nucleus……….. which is positively charged. e) The nucleus of an atom is composed of ………protons…….. and ………neutrons……... f) The ……electrons……….. in an atom move about in the space surrounding the nucleus. g) An uncharged atom has equal numbers of ………protons…….. and ……electrons………... h) A charged atom is called an ……ion………... i) An uncharged atom becomes charged as a result of transferring ……electrons.. to or from it.
3. In an experiment, an insulator becomes negatively charged when it is rubbed with a dry cloth. a) In terms of electron transfer, explain why the insulator becomes negatively charge The insulator gains electrons from the dry cloth when they rub together. This rubbing gives the insulator a negative charge and the cloth a positive charge. j) Explain why the insulator does not lose its charge. When you rub the cloth, you cause the electrons in the cloth to repel the electrons in the insulator. But since these electrons cannot leave their atoms, they reform their orbits around the atoms in such a way that they begin to spend more time on the side of the atom which is the side opposite that of the electrons of the dry cloth.
4. A positively charged object, X, and another charged object, Y, repel each other. a) What is the type of charge on Y? Positive k) Y is removed and a negatively charged object, Z, is brought near to X. State whether X