Chapter 2
Amine
-NH2 (amino group)
Cr2S3
3 S-2 -6 so Cr is +3 (6/2) chromium(III) sulfide
A Z X O
A=mass number Z=Atomic number X=Element O= number of atoms
Predict the chemical formula for the ionic compound formed by the elements Ba and S
BaS
FeCl2
Iron (II) Chloride 2 Cl- -2 so Fe is +2
True or False All atoms of a given element are identical, having the same size, mass and chemical properties. The atoms of one element are different from the atoms of all other elements.
True
What is the correct IUPAC name for Co(NO₂)₂?
cobalt(II) nitrite Nitrite Name stays the same. -do not add ide.
polyatomic ion
contains more than one atom Ex. OH-, CN-, NH4+, NO3
Element are composed of
extremely small particles called atoms.
p=e when
the element is neutral
Rutherford's experiment
the experiment that proved the nucleus must be positively charged (as alpha particles were scattered/deflected by a piece of gold foil).
Atomic Number (Z)
the number of protons in the nucleus of an atom
Groups
vertical columns on the periodic table that have common properties
Is Water (H2O), carbon dioxide (CO2) and methane (CH4) compounds?
yes, because each is made from more than one element.
What is the mass of a proton?
1840 x mass of e- (1.67 x 10-24 g)
What is the difference between a molecule and a compound?
A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements.
Compound
All compounds are molecules but not all molecules are compounds.
An atom of the isotope ¹³³Cs contains how many protons (p), neutrons (n), and electrons (e)? A) 55 p, 55 n, 55 e B) 55 p, 78 n, 55 e C) 133 p, 133 n, 133 e D) 55 p, 133 n, 55 e E) 133 p, 55 n, 55 e
B) 55 p, 78 n, 55 e Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons. The standard notation for an isotope is to indicate the mass number because its protons and electrons do not change mass number element mass number element The symbol 133C indicates that the mass number is 133. Cesium has an atomic number of 55, indicating it has 55 protons, and 55 electrons in the neutral atom. The mass number of an atom is representative of the number of protons and neutrons. Calculate the number of neutrons from the mass number and the number of protons. 133=55+x 78=x
Chemical nomenclature rules for ionic compounds
Put the name of cation before the name of the anion (Al(NO3)2 -> aluminum nitrate) -Often a metal + nonmetal-Anion (nonmetal), add "ide" to the element name
Molecular formula
Shows the exact number of atoms of each element
empirical formula
Shows the simplest whole # ratio of atoms
How many protons are in an atom of strontium-90? A) 2 B) 38 C) 87.62 D) 90
Strontium has an atomic number of 38. The atomic number is the number of protons in an atom.
ionic compound formula
The subscript of the cation is numerically equal to the charge of the anion, and the subscript of the anion is numerically equal to the charge of the cation.
How many neutrons are in an atom of uranium-235? A) 92 B) 143 C) 235 D) 238.0
Uranium-235 has a mass of 235. Uranium always has 92 protons. Therefore, uranium-235 has 143 neutrons.
Ball and Stick Model
Uses balls to represent atoms and sticks to represent chemical bonds
Predict the chemical formula for the ionic compound formed by V³⁺ and NO₂
V(NO₂)₃
Columns
Vertical blocks of text in which text flows from the bottom of one column to the top of the next
Write the empirical formula corresponding to Al₂Br₆
Write the empirical formula corresponding to Al₂Br₆ AlBr₃
space-filling model
a model of a molecule showing the relative sizes of the atoms and their relative orientations
Compounds
are composed of atoms of more than one element. In any compound, the ratio of the numbers of atoms of any two of the elements present is either an integer or a simple fraction.
Hydrates
are compounds that have a specific number of water molecules attached to them.
Are (H2), (O2) and (N2) compounds?
No, they are not compounds because each is composed of a single element
Covalent compounds
Nonmetals or nonmetals + metalloids −Common names−H2O, NH3, CH4, - compound can be formed from the same elements, use prefixes to indicate number of each kind of atom Last element name ends in ide
Dalton' s atomic theory
Nucleus has p, e, and n, which are in an atom.
Alcohol
OH-
Period
A horizontal row of elements in the periodic table
How to find neutrons
mass number - atomic number
Law of Conservation of Mass
matter can neither be created nor destroyed.
Predict the chemical formula for the ionic compound formed by the elements Li and H
LiH The Cation always goes before the anion.
Element
Material with only one type of atom.
Determine the correct formula for manganese(II) fluoride.
MnF₂ The (II) in manganese(II) fluoride indicates that the manganese ion has a 2+ charge. Fluoride has a -1 charge. Two fluoride ions would be needed to balance the charge on the manganese ion.
Mass number (A)
number of protons + number of neutrons = atomic number (Z) + number of neutrons
Cation
on with a positive chargeIf a neutral atom loses one or more electrons it becomes a cation.
proton (p) has ___________ (+) charge of electron (-)
opposite
Nuclear Structure
small positively charged nucleus surrounded by empty space and a thin layer of electrons to form outside of the atom. Nuclear Structure
A row on the periodic table
"Period" All the elements in a period have valence electrons in the same shell. The number of valence electrons increases from left to right in the period
What is the mass number for an atom of barium containing 56 protons and 82 neutrons?
.The mass number of an atom is representative of the number of protons and neutrons. The number of protons can be found from the atomic number of the element on the periodic table. Calculate the mass number using the given number of protons and neutrons. For example, if there are 56 protons and 82 neutrons, the mass number can be calculated like this: 56+82=138
Melatoids
8 elements on the staircase (B, Si, Ge, As, Sb, Te, Po, At) properties of metal and non metal depending on temp
A molecule has an empirical formula of CH, and its molar mass is known to be 26 g/mol. What is its molecular formula? A) CH B) CH₂ C) C₂H₂ D) C₂H E) C₃H₃
C) C₂H₂ An empirical formula shows the simplest ratio of each element to one another. One carbon atom and one hydrogen atom, CH, have a relative mass of 13 g/mol. If the molar mass of a molecule is 26 g/mol, this would have two carbon atoms and two hydrogen atoms, giving the formula C₂H₂.
carboxyl group
COOH
How many electrons are in a neutral ⁴¹Ca atom? A) 2 B) 20 C) 21 D) 41
Calcium has 20 protons. Therefore a neutral calcium atom has 20 electrons.
What group (G) and period (P) does the element molybdenum (Mo) belong to? A) G = 5, P = 6 B) G = 6, P = 6 C) G = 6, P = 4 D) G = 6, P = 5 E) G = 5, P = 5 +
D) G = 6, P = 5
Classify the following compounds as ionic or covalent: BaO, Fe₂O₃, ZnO. A) Covalent, covalent, covalent. B) Ionic, ionic, covalent. C) Ionic, covalent, covalent. D) Ionic, Ionic, Ionic.
D) Ionic, Ionic, Ionic. Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two nonmetals.
Which of the following elements would be chemically similar to selenium (Se)? A) Br B) Sc C) As D) S E) Ca + Question 40 of 95
D) S Elements that are in the same family (column) on the periodic table are chemically similar. S is in the same family as Se.
valence electron
Electrons on the outermost energy level of an atom. Full outer shell is 8 valence electrons.
Halogens
Group 7A group 17; contains nonmetals; 7 electrons in its outermost energy level;
FeCl3
Iron (III) Chloride 3 Cl- -3 so Fe is +3
Which of the following pairs represent isotopes? A) ²⁸Si and ²⁸Si⁴⁺ B) ²⁸Si and ²⁸Al C) ²⁸Si and ²⁹Si D) ²⁸Si and ²⁸Si⁴⁻ E) ²⁸Si⁴⁺ and ²⁸Al³⁺
Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons. The standard notation for an isotope is to indicate the mass number because its protons and electrons do not change ²⁸Si and ²⁹Si
Isotopes
are atoms of the same element (X) with different numbers of neutrons in their nuclei
How would you name BaCl2?
barium chloride
Acid
can be defined as a substance that yields hydrogen ions (H+) when dissolved in water.
base
can be defined as a substance that yields hydroxide ions (OH-) when dissolved in water.
ionic compounds
compounds composed of cations and anions metal and nonmetal • The formula is usually the same as the empirical formula• The sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero.
Polyatomic molecule
contains more than two atoms Ex. O3, H2O, NH3, CH4
monatomic ion
contains only one atom ex Na+, Cl-, Ca2+, O2-, Al3+, N3-
diatomic molecule
contains only two atoms Ex. H2, N2, O2, Br2, HCl, CO
hydrohalic acid
hydrogen and halogen
Name the following HI NF3 SO2 N2Cl4 NO2 N2O
hydrogen iodide nitrogen trifluoride sulfur dioxide dinitrogen tetrachloride nitrogen dioxide dinitrogen monoxide
Where is there a positive charge in the atom?
in the nucleus
Transition metal ionic compounds
indicate charge on metal with Roman numerals
Chemical reaction
involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction.
Anion
ion with a negative chargeIf a neutral atom gains one or more electrons it becomes an anion.
The most reactive metals (green) and the most reactive nonmetals (blue) combine to form
ionic compounds.
oxoacid
is an acid that contains hydrogen, oxygen, and another element.
Molecule
is an aggregate of two or more atoms in a definite arrangement held together by chemical forces Ex. H2 and H20 , NH3 and CH4
ion
is an atom, or group of atoms, that has a net positive or negative charge.