Test for Physical science

Methanes chemical formula is _____

(CH4)

Know name of a compound

(H2O) = hydrogen and oxygen (NaCl) = ion and sodium chloride (Co2) = carbon dioxide (NH3) = Ammonia (CH4) = Methan ( CCl4) = Carbon tetrachloride

By losing an electron, the sodium atom becomes a sodium ion with a charge of _____ ___

+1

by gaining an electron, the chlorine atom becomes a chloride ion with a charge of _____

- 1

Know how to draw a Lewis dot diagram for compound

Carbon dioxide (CO2) and Ammonia (NH3)

When chlorine becomes an ion, the name changes to _____

Chloride

Electrons in the innermost levels, do not bond with other elements, because they are ______ by the outermost valence electrons

shield

The salt in food is a compound of two elements

sodium and chlorine

The _____ 2 indicates there are 2 atoms of hydrogen in a water molecule

subscript

The ion charge is written as a ____ after the element symbol

superscript

A dot diagram shows the element _____ surrounded by one to eight dots representing its ____ ____

symbol and valence electrons

A chemical bond forms when atoms _____ or _____ electrons

transfer and share

ionic bonds are bonds in which one or more electrons are ____ from one atom to another

transferred

for example, the chemical formula for water is

H2O

KNow which has less energy

Methane (CH4) lower energy

KNow how to draw a Lewis dot diagram for elements

Neon (Ne), fluorine (F), oxygen (O), nitrogen (N), carbon (C), and hydrogen (H)

A sodium atom is _______ with 11 positively charged protons and 11 negatively charged electrons. When sodium loses 1 electrons, it has 11 protons and ___ electrons, and becomes and ____ with a net charge of ____ ____

Neutral, 10, ion and +1

They are ____ by themselves

Poisonous

Know the change if gains or loses an electron bond

Sodium = 1 valence electron Chlorine = 7 valence electrons

A molecule's _____ _____ tells you the ratio of atoms of each element in the compound

chemical formula

this means we can use the same type of _____ ____ for ionic compounds and covalent compounds

chemical formula

Most Matter exist as _____, not as pure elements

compounds

when atoms gain or lose electrons, they become

ions

Bonded atoms have ____ total energy than the same atoms separately

less

Atoms form bonds to form a _______ energy state

lower

A group of atoms held together by covalent bonds is called a ______

molecule

All elements expect the ____ ____ form chemical bonds

noble gases

Compounds contain particular _____ of elements

ratios

The closer number an element has to a 2 or 8, the more _____ it is

reactive

Group 1 and group 17 are more _____ because 1 wants to give up or release the one electron in the outside energy level

reactives

Energy is ____ when chemical bonds form

released

A covalent bond is formed when atoms _____ electrons

share

The difference is that in sodium chloride, the electron is transferred instead of _____ from the sodium atom to the chlorine atom

shared

____ or _____ are stable numbers for hydrogen

0 or 2

Each dot represents ____ electron

1

Li has ____ valence electron

1

Be has _____ in outer level

2

Know how many valence electrons an element has

2 or 8

Carbon has 4 dots and hydrogen 1, one carbon atom bonds with four hydrogen atoms, giving the carbon _____ valence electrons

8

______ is the stable number for chemical bonding

8

They chemically form chemical bonds to make _______

Compounds

KNow an iconic bond from a covalent bond

Covalent bond: a chemical bond formed by atoms that share one or more electrons Ionic bond: bond that transfer one or more electrons

A ______ ______ ______ is a way to represent an atom's valence electrons

Lewis Dot Diagram

The electrons in the highest, unfilled energy level of an atom are called ____ ______

Valence electrons

in an ionic compound,each atom bonds with _____ its neighbors through attraction between positive and negative charges

all

Know which element bond with which element

carbon = hydrogen

Sodium chloride involves the transfer of one ____. However, ionic compounds may also be formed by the transfer of ___ or more electrons. The magnesium atom gives up two electrons to become a magnesium ion with a charge of ___ ___. Each chlorine atom gains one electron to become a chloride ion with a charge of ___ ___

electron, two, +2, and -1

Like covalent compounds, ionic compounds have ____ ____ of elements

fixed ratios

______ can bind with almost any element

hydrogen

Example is H2O is a compound of ______ and _____

hydrogen and oxygen

an _____ is a charged atom

ion

sodium and chlorine form an ____ ___, because the positive sodium ion is attracted to the negative chloride ion

ionic bond

That's because more pure elements are chemically _______

unstable

KNow how to tell if element is highly reactive, moderate, or not

very reactive - elements readily forms chemical bonds, often releasing energy Ex: sodium and chlorine