Atoms and atomic theory
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English-for-Chemistry-1-After-lesson-1
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fractional. When the electrons of a covalent bond are shared unequally, the bond is called a polar covalent bond. Due to the unequal sharing of the electrons in the bond, a polar covalent bond has one atom with a partial positive charge, δ+, and one atom with a partial negative charge, δ−. Sometimes one atom in a bond attracts electrons so much more strongly than the other that one or more electrons are fully transferred from one atom to another. This commonly happens when metallic atoms combine with nonmetallic atoms. A nonmetallic atom usually attracts electrons so much more strongly than a metallic atom that one or more electrons shift from the metallic atom to the nonmetallic atom. For example, when the element sodium combines with the element chlorine to form sodium chloride, NaCl, the chlorine English in chemistry 1 – 2017 TS. Nguyễn Tuyết Phương – TS. Trần Thu Phương 12 atoms attract electrons so much more strongly than the sodium atoms that one electron is transferred from each sodium atom to a chlorine atom. When an electron is transferred completely from one uncharged atom to another, the atom that loses the electron is left with one more proton than electron and acquires a +1 charge overall. It therefore becomes a cation. In contrast, an uncharged atom that gains an electron will have one more electron than proton, so it forms an anion with a -1 charge. Because particles with opposite charges attract each other, there is an attraction between cations and anions. This attraction is called an ionic bond. Q1. Complete the following statements by writing one of these words or phrases in each blank negligible (or zero) gains single atom ionic loses covalent bond eight noble gas covalent ion 1. Each noble gas particle consists of a(n) __________. 2. When an atom _______ one or more electrons, it will have more protons than electrons and more plus charge than minus charge. Thus it becomes a cation, which is an ion with a positive charge. 3. When an atom _______ one or more electrons, it then has more electrons than protons and more minus charge than plus charge. Thus it becomes an anion, which is an ion with a negative charge. 4. An atom or group of atoms that has lost or gained one or more electrons to create a charged particle is called a(n) __________. 5. A(n) __________ bond is a link between atoms that results from the sharing of two electrons. 6. When the difference in electron‑attracting ability between atoms in a chemical bond is __________, the atoms in the bond will have no significant partial charges. We call this type of bond a nonpolar covalent bond. 7. When a nonmetallic atom bonds to another nonmetallic atom, the bond is __________. 8. When a metallic atom bonds to another nonmetallic atom, the bond is _______. 9. Nonmetallic atoms form anions to get the same number of electrons as the nearest __________. English in chemistry 1 – 2017 TS. Nguyễn Tuyết Phương – TS. Trần Thu Phương 13 10. When atoms other than the noble gas atoms form bonds, they often have _______ electrons around them in total. tải về 0.52 Mb. Chia sẻ với bạn bè của bạn:
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