Chapter 4

- when an atom loses a valence electron, it loses a negative charge. it becomes a positive ion. - when an atom gains an electron, it gains a negative charge and becomes a negative ion

- Formulas: for an ionic compound, write the symbol of the positive ion and then the symbol of the negative ion. add the subscripts that are needed to balance the charges - Names: for an ionic compound, the name of the positive ion comes first, followed by the name of the negative ion

- form hard brittle crystals that have high melting points - conduct electric current when dissolved in water or melted

because their valence ring is filled with electrons and no space for more electrons

electrons that have the highest energy, they determine the chemical properties of its element

shows the chemical symbol with dots surrounding it to represent the valence electrons of that atom

the force of attraction that holds atoms together as a result of the rearrangement of electrons between them. (energy is stored here)

they want to be more stable by filling up their valence ring with valence electrons

its amount of valence electrons

Except for period 1, elements in a group always have the same number of valence electrons. This gives them similar properties

they lose their valence electrons

how easily the atom loses it's valence electrons

it decresses

they can gain or share valence electrons to have a full valence ring

metals, by gaining electrons

yes, other nonmetals or metalloids by sharing electrons

(Group 17) They easily react with other elements because they only need to gain one electron as they have 7 valence electrons

They can lose or share electrons when they combine with other elements

1- it is a nonmetal on the metal side of the table 2- has very different properties than the alkali metals. 3- Hydrogen always shares its electron when forming compounds with other nonmetals to obtain a stable arrangement of 2 electrons.

Makes an element stable and nonreactive

an atom or group of atoms that has an electric charge

Ions that are made of more than one (1) atom, can have an overall positive or negative charge

the attraction between two oppositely charged ions

made up of an equal amount of positive and negative ions

symbols that shows the ratio of elements in a compound

a number that is written below and behind the chemical symbols in a chemical formula.

The ions form an orderly, three-dimensional arrangement.

the chemical bond formed when 2 atoms share electrons

the attractions between the shared electrons and the protons in the nucleus of each atom hold them together.

a molecule is a neutral group of atoms joined by covalent bonds

a chemical bond in which one pair of electrons is shared between 2 atoms.

2 atoms share 2 pairs of electrons

when two atoms share 3 pairs of electrons

a compound that is made up of molecules

a covalent bond when electrons are shared equally

a covalent bond when the electrons are shared unequally

unlike ionic compounds, molecular compounds usually do not conduct electric current when melted or dissolved in water. - also compared to ionic compounds, molecular compounds generally have lower melting and boiling points

unequal sharing of electrons causes covalently bonded atoms to have slight electric charges

A bond formed by the attraction between positively charged metal ions and the electrons around them.

Mixture made of two or more elements, at least one of which is a metal.

It is composed of closely packed, positively charged metal ions. The valence electrons drift among the ions.

(again) shiny luster, high levels of malleability, ductility, electrical conductivity and thermal conductivity

paper

- how many valence electrons an atom has - the elements on the outside ring only - the valence electrons on the valence ring

polar: -uneven sharing of electrons -element with higher atomic # -has more attraction nonpolar: -equal atomic # -share = electrons -diatomic (same element)

chemical properties

positive negative

because their not chemical bonds, an their valence electrons are allowed to move freely around their ring so they have more space. for heat, the more energy the electrons have, the warmer the atom gets and by being able to move around that should cause a lot of energy

non polar: the bond of 2 hydrogen atoms because they equally share their pair of electrons to form a molecule - polar bond: water, h2o, oxygen spends more time with the electrons then the 2 hydrogen atoms do