Chapter 3 Test Flashcards
What surrounds the nucleus in an atom
a cloudlike region of moving electrons
Where does most of the volume in an atom come from
the space in which electrons move
What is the symbol for an electron
e-
What is the charge of a neutron
0
How many electrons does it take to equal the mass of a proton
1,840
What unit is used to measure the mass of an atom
Atomic Mass Units
What is an atomic number
the number of protons in an element’s atom’s nucleus
What is a valence electron
the electrons in an atom with the highest amount of energy
Which atom is involved in chemical bonding
Valence electrons
What helps determine the chemical properties of an element
the number of valence electrons
What is the range of valence electrons an element can have
1 - 8
What is an electron dot diagram
a diagram of the symbol of the element and dots around it representing valence electrons
What element is stable with 2 val. electrons
Helium
What element only needs to gain 1 val. electrons to be stable
Hydrogen (keeps a stable 2)
What is a chemical bond
the force of attraction that holds atoms together as a result of the rearrangement of electrons between them
What group is the noble gasses
group 18 (Helium has 2 Val. electrons)
Do Noble Gasses react easily
no
How do metal atoms react
by losing their val. electrons
What group are Alkali metals in
group 1
What group are Halogens in
group 17
What does the reactivity of metal depend on
how easily its atoms lose val. electrons (the reactivity of metals reduces from left to right on the periodic table)
When Alkali metals (group 1) lose an electron they gain a stable arrangement of __ val. electrons
8
How reactive are Alkali metals
highly reactive
How do nonmetals become stable
they gain/share enough electrons to have 8 val. electrons (except the weirdo in the corner: Hydrogen who keeps a stable 2)
Can Halogens easily react with other elements
yes (they gain 1)
Where are the metalloids on a periodic table
along the zigzag line
how do metalloids combine with other elements
by losing or gaining electrons
What is an ion
an atom/group of atoms with an electric charge
When a neutral atom loses a valence electron it’s charge becomes ______
positive
What is a polyatomic ion
an ion made of several elements
What is an ionic bond
the attraction between 2 oppositely charged ions (metal <3 nonmetals)
What is an ionic compound
the result of an ionic bond (a compound made of oppositely charged ions)
What is a chemical formula
a group of symbols that shows the ratio of elements in a compound
How is the name of an ionic compound writen
The name of the positive ion first then the negative one
What does the suffix -ide mean in ionic compounds
that the negative ion is a single element
What does the suffix -ate/-ite mean in ionic compounds
that the negative ion is polyatomic
What crystals do ionic compounds form
hard, brittle crystals with high melting points which conduct electricity when dissolved in water or melted
How do the ions in a compound need to be to conduct electricity
free moving
What is a covalent bond
the bond between 2 atoms which share electrons
What is a molecule
a neutral group of atoms joined by covalent bonds
What is a double bond
When atoms share 2 pairs of electrons
What is a triple bond
When atoms share 3 pairs of electrons
What is a molecular compound
a compound made of molecules (covalently bonded)
Which type of compound doesn’t conduct electricity and has a low melting point
molecular compound
Why are molecular compounds poor conducters
because they don’t comtain charged particles
Why do molecular compounds have a low melting point
because it’s bonds are weaker
What does unequal sharing of electrons cause to covalently bonded atoms
it causes them to have slight electric charges
What is a nonpolar bond
a covalent bond where electrons are shared equally
What is a polar bond
a covalent bond where electrons are shared unequally (causes the atoms to have slight charges)
What are van der Waals forces
The attractions in Polar molecules between slight negative and positive charges
Which has stronger attraction? polar or nonpolar
polar
Why do metal atoms easily lose electrons
because they do not hold onto them strongly
What is a metal crystal composed of
closely packed, positively charged metal ions with valence electrons drifting among the ions
What is a metallic bond
an attraction between a positive metal ion and the surrounding electrons
What are the properties of metals
shiny luster and high levels of malleability, ductility, thermal and electrical conductivity
Why does metal have a shiny and reflective luster
because the valence electrons absorb and remit light
What does it mean if something is ductile
it can easily be dent and pulled into wire
What does it mean if something is malleable
it can be rolled into (thin) sheets and hammered into shape
Why are metals ductile and malleable
because positive metal ions are attracted to the loose electrons around them rather than to other metal ions
Why do metals have high thermal and electrical conductivity
because the electrons are free to move
What is an alloy
a mixture of 2 or more elements of at least one is metal
