Section 5.1

Each element has a specific number of valence electrons, ranging from __ to __.

1/8

Oxygen has ___ valence electrons

6

______________ is the most reactive element known and even forms compounds with some of the noble gases.

Fluorine

___________________ has only one valence electron

Hydrogen

_________________ can behave as either metals or nonmetals, depending on the conditions.

Metalloids

_________________ can either lose or share electrons when they combine with other elements.

Metalloids

Atoms of the __________ metals, Group 1, have only one valence electron.

alkali

Some metals, such as those in Group 1 (the _____________________), lose electrons easily and are almost as reactive as the alkali metals of Group 1.

alkaline earth metals

A ______________________ is the force of attraction that holds two atoms together as a result of the rearrangement of electrons between them.

chemical bond

One of two things can happen: Either the number of valence electrons increases to eight (or two, in the case of hydrogen). Or, the atom gives up loosely held valence electrons. Atoms that react that way can become _______________________, that is, bonded to other atoms.

chemically combined

Elements with eight valence electrons do not easily form a _______________

compound

Chemists have been able to make noble gases form ____________________ with a few other elements.

compounds

In general, the reactivity of metals _________________ from left to right across the periodic table.

decreases

As a result, the halogens react _______________ with other elements whose atoms can give up or share electrons.

easily

Atoms with ____________ valence electrons are unlikely to transfer electrons to other atoms or to share electrons with other atoms

eight

Except for Period 1, a period ends when the number of valence electrons reaches _________

eight

Except for lithium, the next lowest energy level has a stable set of ___________ electrons. (Lithium atoms have a stable set of two electrons at the next lowest energy level.)

eight

The noble gases have __________ valence electrons

eight

An ________________________ includes the symbol for the element surrounded by dots.

electron dot diagram

The periodic table gives you information about the arrangement of _______________ in atoms.

electrons

When atoms bond, ____________ may be transferred from one atom to another, or they may be shared between the atoms.

electrons

All of the nonmetals have __________ or more valence electrons.

four

Like the halogens, other nonmetals become stable when they ____________ or share enough electrons to have a set of eight valence electrons.

gain

Unlike the metals, most nonmetals are __________ at room temperature.

gases

The elements in Group 17, the _______________, have atoms with seven valence electrons. A gain of just one more electrons gives these atoms the stable number of eight electrons, as in the noble gases.

halogens

Some small atoms, such as ___________, are stable with just two valence electrons

helium

The next period begins with atoms having valence electrons with ___________ energy.

higher

Of the nonmetals, oxygen and the halogens are _______________________.

highly reactive

Among Groups 1 and 2, reactivity ________________ from top to bottom.

increases

As the atomic number increases, the number of electrons _________________.

increases

Five nonmetals are solids, and one is a __________.

liquid

How reactive a metal is depends on how easily its atoms ___________ valence electrons.

lose

The ____________ have from three to six valence electrons

metalloids

The nonmetals combine with _____________ usually by gaining electrons

metals

As a result, ________________ do not react easily with other elements.

noble gases

The Group 18 elements are the _________________

noble gases

Hydrogen is considered to be a _________________

nonmetal

Elements in the green section of the periodic table are the __________________.

nonmetals

Elements with one, two, or three valence electrons react by losing valence electrons, especially when they combine with ______________ or one of the halogens.

oxygen

The elements within a group have similar _________________ because they all have the same number of valence electrons in their atoms.

properties

In either case, the change results in a chemical _______________ -- that is, new substances form.

reaction

Alkali metal atoms can become chemically more stable by losing one valence electron. This property makes the alkali metals very _______________.

reactive

Hydrogen is a ________________ element, but its properties differ greatly from those of the alkali metals.

reactive

Nonmetals can also combine with other nonmetals by _______________ electrons.

sharing

Atoms of most elements are more _______ - that is, less likely to react - when they have eight valence electrons.

stable

Atoms usually react in a way that makes each atom more ___________

stable

Other metals, such as platinum in Group 10 and gold in Group 11, are ___________________.

unreactive

Each dot in an electron dot diagram stands for one _____________________.

valence electron

An atom's ______________________ are those electrons that have the highest energy level and are held most loosely.

valence electrons

If you know the number of ____________________ that atoms of different elements have, you have a clue to which elements combine and how.

valence electrons

The number of ____________________ in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.

valence electrons

This repeating pattern means that the elements within a group, or column, always have the same number of __________________.

valence electrons