Unit One: Chemical Reactions
1st Prep. Science
2nd Term
Unit One: Chemical Reactions Lesson One: Chemical Combination
Metals They have less than (4) electrons in the outermost energy level. They are solids [except mercury (Hg) which is a liquid]. They have metallic luster. They are malleable and ductile. They are good conductors of heat and electricity. During the chemical reaction, atoms of metals tend to lose electrons and change into positive ions.
P.O.C. Electrically The number of electrons
Nonmetals They have more than (4) electrons in the outermost energy level. They are solids and gases [except bromine (Br) which is a liquid]. They have no luster. They are not malleable or ductile. They are bad conductors of heat and electricity. [Except graphite which is a good conductor of electricity]. During the chemical reaction, atoms of nonmetals tend to gain electrons and change into negative ions.
Atom Neutral in ordinary state. Equals the number of protons.
Positive ion [Cation] It is an atom of metallic element that loses an electron or more during chemical reaction. It carries positive charges equal to the number of the lost electrons. The number of its electrons is less than the number of protons inside the nucleus. The number of its energy levels is less than that of its atom.
Inert gases Their outermost shells are completely filled with electrons, so they don’t participate in any chemical combination in ordinary conditions. Each molecule consists of one single atom [Monoatomic].
They don’t form positive or negative ions in the ordinary conditions.
Ion Charged [Positive or negative ions]. Is more than or less than the number of protons.
Negative ion [Anion] It is an atom of nonmetallic element that gains an electron or more during chemical reaction. It carries negative charges equal to the number of the gained electrons. The number of its electrons is more than the number of protons inside the nucleus. The number of its energy levels is equal to that of its atom.
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1st Prep. Science
2nd Term
Chemical bonds: 1. Ionic bond: It is a bond resulting from the electric attraction between a positive ion and a negative ion.
2. Covalent bond: It is a bond occurred among the atoms of nonmetals through the participation of each atom with the same number of electrons to complete the outer electron shell of each atom.
H2 [H–H ] H2O [H–O–H]
O2 [O=O]
Ionic bond It is formed by losing and gaining of electrons. It arises between metal and nonmetal elements. It is formed between 2 atoms of two different elements. It is formed due to the electrical attraction between the positive and negative ions. It has one type. It produces compound molecules only.
N2 [N N]
Covalent bond It is formed by sharing of one pair of electrons or more. It arises between two nonmetals elements. It may be formed between 2 atoms of the same element. It is formed due to sharing of electrons between the atoms. It has three types [Single, double and triple]. It produces elements and compound molecules.
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2nd Term
Unit One: Chemical Reactions Lesson One: Chemical Combination
Metals They have less than (4) electrons in the outermost energy level. They are solids [except mercury (Hg) which is a liquid]. They have metallic luster. They are malleable and ductile. They are good conductors of heat and electricity. During the chemical reaction, atoms of metals tend to lose electrons and change into positive ions.
P.O.C. Electrically The number of electrons
Nonmetals They have more than (4) electrons in the outermost energy level. They are solids and gases [except bromine (Br) which is a liquid]. They have no luster. They are not malleable or ductile. They are bad conductors of heat and electricity. [Except graphite which is a good conductor of electricity]. During the chemical reaction, atoms of nonmetals tend to gain electrons and change into negative ions.
Atom Neutral in ordinary state. Equals the number of protons.
Positive ion [Cation] It is an atom of metallic element that loses an electron or more during chemical reaction. It carries positive charges equal to the number of the lost electrons. The number of its electrons is less than the number of protons inside the nucleus. The number of its energy levels is less than that of its atom.
Inert gases Their outermost shells are completely filled with electrons, so they don’t participate in any chemical combination in ordinary conditions. Each molecule consists of one single atom [Monoatomic].
They don’t form positive or negative ions in the ordinary conditions.
Ion Charged [Positive or negative ions]. Is more than or less than the number of protons.
Negative ion [Anion] It is an atom of nonmetallic element that gains an electron or more during chemical reaction. It carries negative charges equal to the number of the gained electrons. The number of its electrons is more than the number of protons inside the nucleus. The number of its energy levels is equal to that of its atom.
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1st Prep. Science
2nd Term
Chemical bonds: 1. Ionic bond: It is a bond resulting from the electric attraction between a positive ion and a negative ion.
2. Covalent bond: It is a bond occurred among the atoms of nonmetals through the participation of each atom with the same number of electrons to complete the outer electron shell of each atom.
H2 [H–H ] H2O [H–O–H]
O2 [O=O]
Ionic bond It is formed by losing and gaining of electrons. It arises between metal and nonmetal elements. It is formed between 2 atoms of two different elements. It is formed due to the electrical attraction between the positive and negative ions. It has one type. It produces compound molecules only.
N2 [N N]
Covalent bond It is formed by sharing of one pair of electrons or more. It arises between two nonmetals elements. It may be formed between 2 atoms of the same element. It is formed due to sharing of electrons between the atoms. It has three types [Single, double and triple]. It produces elements and compound molecules.
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