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Ch. 5 Science
Question | Answer |
---|---|
valance electron | the electrons that are in the highest energy level of an atom and that are involved in chemical reactions |
electron dot diagram | a representation of the valence electrons in an atom,using dots |
chemical bond | the force that holds atoms together |
The number of valence electrons in an atom of an element determines the ways in which the atom can bond | true |
when atoms form bonds, electrons may be transferred or shared between atoms | true |
how is the periodic table organized | increasing atomic number |
what is the row of elements across the periodic table called? | period |
what id the greatest number of valence electrons an atom can have? | 8 |
what are elements in the same column of the periodic table called? | group/family |
what happens to the reactivity of metals from left to right across the periodic table? | it decreases becoming more stable |
how many valence electrons can non metals have/ | four or more |
what are 2 ways that nonmetals can combine with other elements | by gaining electrons and by sharing electrons |
how many valence electrons does a hydrogen atom have? | 1 |
Hydrogen is considered to be a metal | false |
ion | an atom or group of atoms that has become electrically charged |
polyatomic ion | an ion that is made of more than one atom |
ionic bond | the attraction between oppositely charged ions |
ionic compound | a compound that consists of positive and negative ions |
chemical formula | a combination of symbols that represents the elements in a compound and their proportions |
subscript | a number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound |
crystal | a orderly, three-dimensional pattern of ions or atoms in a solid |
what are two ions that can form an ionic bond | sodium and chloride |
what happens to an atom when it loses an electron? | it looses a negative charge and becomes a positive ion. When an atom gains an electron. it gains a negative charge and becomes a negative ion |
what happens to an atom when it gains an electron? | it gains a negative charge and becomes a negative ion |
when ionic compounds form, the ions come together in a way that balances out the charges on the ions | true |
for an ionic compound, the name of the negative ion comes first | false |
what are three characteristic properties of ionic compounds | 1. hard brittle crystals 2. high melting point 3. electrical conductivity when melted |
in an ionic compound, which ions are attracted to each other | every ion is attracted to ions of opposite charge |
why do ionic compounds have high melting points? | because ionic bonds are strong, a lot of energy is needed to break them. They are all solids at room temperature. |
At room temperature, ionic bonds are strong enough to cause all ionic compounds to be... | solids |
covalent bond | a chemical bond formed when 2 atoms share electrons |
molecule | a neutral particle made up of 2 or more atoms joined by covalent bonds |
double bond | a chemical bond formed when atoms share 2 pairs of electrons |
triple bond | a chemical bond formed when atoms share 3 pairs of electrons |
molecular compound | a compound that is composed of molecules |
polar bond | a covalent bond in which electrons share are shared unequally |
nonpolar bond | a covalent bond in which electrons are shared equally |
alloy | a mixture of 2 or more elements, one of which is a metal |
metallic bond | an attraction between a positive metal ion and the electrons surrounding it |
atoms of some elements can share three pairs of electrons | true |
how are atoms arranged in molecular compounds | arranged in molecules |
how are electrons shared in a nonpolar covalent bond? | shared equally |
Water molecules are polar | true |
what are 4 properties of metals | heat conductivity, electrical conductivity, luster, and changes in state |
what does a metal crystal consist of | positively charged metal ions embedded in a "sea" of valence electrons |