8th Science Chapter 4 Atoms, Bonding, and the Periodic Table

The number as the number of electrons.
What is the number of protons in a neutral atom?
They have higher amounts of energy.
What happens to the energy of electrons as higher energy levels?
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They are the electrons of an atom that have the most energy. They are involved in chemical bonding.
What are valence electrons?
1 to 8
How many valence electrons can an atom have?
The symbol of the element surrounded by dots. There is one dot for each valence electron.
What does an electron dot diagram include?
Those with 8 valence electrons. They are nonreactive. Examples: Neon, Argon, Kryton, Xenon
What atoms tend to be the most stable?
Chemical bond
The force of attraction that holds atoms together as a result of the rearrangement of electrons between them.
they react by losing their valence electrons
How do metals react
The metals in group 1 are the most reactive and the reactivity decreases as you go left to right on the table.
How is the reactivity of metals shown on the periodic table?
One
How many valence electrons do metals in group one have?
They are so reactive that they can cause an explosion when added to water.
How reactive are the alkali metals in group one?
blue
What color are the metals on the periodic table?
orange
What color are the nonmetals on the periodic table?
When they gain or share enough electrons to have 8 valance electrons.
When do nonmetal atoms become stable?
They gain electrons.
How do nonmetals usually combine with metals?
They share electrons.
How do nonmetals combine with other nonmetals or metalloids?
They zigzag between the metals and nonmetals.
Where are the metalloids on the periodic table?
They can either lose or share electrons when they combine with other elements.
How do metalloids combine with other atoms?
They have some properties of metals and some properties of nonmetals.
What kinds of properties do metalloids have?
Hydrogen shares its one electron when combining with other nonmetals to obtain a stable arrangement of 2 electrons.
Hydrogen is in Group 1 because it has one valance electron but it is considered a nonmetal. Hydrogen is different from the alkali metals. Describe how it combines with other nonmetals.
ion
an atom or group of atoms that has an electric charge.
negative charge, positive ion
When a neutral atom loses a valence electron it loses a ______ charge and becomes a ________ ion.
negative charge, negative ion
When a neutral atom gains an electron, it gains a _____ charge and becomes a _______ ion.
lose, 8, lower
metals are likely to _____ enough electrons to have a stable arrangement of _____ valence electrons at a _____ energy level.
gain, 8
Nonmetals are likely the _____ electrons so that they have ____ valence electrons.
polyatomic
poly means many so polyatomic means many atoms
Ions made of more than one atom
ionic bond
the attraction between two oppositely charged ions
ionic compound
a compound resulting from the attraction between two oppositely charged ions
chemical formula
a group of symbols that shows the ratio of elements in a compound
subscripts
they tell the ratio of elements in a compound
hard, brittle crystals that have high melting points. They conduct electric current when dissolved in water.
In general, ionic compounds form ______
crystal
Ions that form an orderly, three-dimensional arrangement
very high melting points because it takes huge amounts of energy to separate the ions in crystal.
The ions in crystals have to break apart for an ionic compound to melt. So they have _____
conduct electric current
When ionic crystals that dissolve in water they are free to move around and the solution can ________
do not conduct electric current
When ionic compounds are solid form they _______
covalent bond
The chemical bond formed when 2 atoms share electrons
nonmetal atoms
Covalent bonds usually form when between two _______
metal combines with nonmetal atoms
Ionic bonds usually form when ______
covalent
The attractions between the shared electrons and protons in the nucleus of each atom hold the atoms in a ______ bond
double bond
2 atoms that share 2 pairs of electrons form a _______
triple bond
When atoms share 3 pairs of electrons they form a _____
molecular compound
a compound that is made up of molecules
conduct electric current
Unlike ionic compounds, molecular compounds usually do not ___________ when melted or dissolved in water.
lower
Compared to ionic compounds, molecular compounds have ______ melting and boiling points.
no current
Molecular compounds do not contain charged particles that are available to move so there is ________.
No, it needs materials to be dissolved in it to conduct electric current
Does pure water conduct electric current?
slight electric charges
Unequal sharing of electrons causes covalently bonded atoms to have ______
nonpolar bond
a covalent bond in which electrons are shared equally
charged
Nonpolar bonds neither atom becomes _______.
polar bond
A covalent bond in which electrons are shared unequally
a slightly negative charge, slightly positive charge
In a polar bond the atom with the stronger pull gains ______ and the atom with the weaker pull gains a ______
It is made of closely packed, positively charged metal ions. The valance electrons drift among the ions.
What is a metal crystal made of?
metallic bond
an attraction between a positive metal ion and the electrons surrounding it.
A shiny luster, high levels of malleability, ductility, electrical conductivity, and thermal conductivity.
What are the properties of metals?
the behavior of valence electrons in metal atoms
The properties of metals are related to ____.
When light strikes the valence electrons they absorb the light and then re-emit the light.
How is the luster, or shiny quality of metals, related to its valence electrons?
The positive metal electrons are attracted to the loose electrons all around them not to other metal ions. This allows the ions to change position. However, the bonds between the ion and the surrounding electrons keep the metal ions from breaking apart.
How is the malleability and ductility of metals related to its electrons?
The valence electrons in the metal are free to move so electrons in the warmer part of the metal can transfer energy to electrons in the cooler part of the metal.
Why do metals conduct heat easily?
The valence electrons can move freely among the atoms.
Why can metals easily conduct electricity?
alloy
a mixture made up of two or move elements, with at least one being a metal
stronger, less reactive
Alloys are generally ______________ and less ______________ than the pure metals they are made from.
Copper or silver
What is gold is often mixed with to make an alloy that is harder than gold but still shiny like gold?
Iron will rust when exposed to water and air. The alloy steel is stronger and resists rust.
Why is iron often mixed with other elements to make steel.
It can be washed over an over without rusting.
Forks and spoons are made of stainless steel which is an alloy of iron, carbon, nickel, and chromium. Why do they use stainless steel to make forks and spoons?
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