Chemistry chapter 2
How can you determine if something is a Ball-and-stick model?
represent atoms as balls and chemical bonds as sticks
How can you determine if something is a perspective drawings?
show the three-dimensional array of atoms in a compound
What is organic chemistry?
the study of carbon compounds. compounds tat contain carbon and hydrogen, often in combination with oxygen, nitrogen, or other elements.
What is chemical nomenclature?
the systematic naming of chemical compounds
How is an ion formed?
when an atom gains or loses an electron
What is the charge of an electron and of proton? AKA the electronic charge?
-1.602 x 10^-19C for electron BUT you use (1-) +1.602 x 10^-19C for Proton BUT you use (1+)
What are the characteristics of nonmetallic elements/nonmetaks?
-At room temperature and pressure, some of the non metals are gaseous, some are solid, and one is liquid
What are the characteristics properties of metallic elements?
-luster -high electrical and heat conductivity -all of them EXCEPT Mercury (Hg) are solid at room temperature
Every atom has an..
..equal number of electrons and protons, so atoms have no net electrical charge
What charge of ion does group 1A form?
1+ ions
What charge of ion does group 7A form?
1- ions
What was Dalton's atomic theory?
1.) Each element is composed of extremely small particles called atoms 2.) All atoms of a given element are identical, but the atoms of one element are different from the atoms of all other elements. 3.) Atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions 4.) Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of elements .
Names and Formulas of Binary Molecular Compounds
1.) The name of the left farther to the left in the periodic table (closest to the metals) is usually written first. An exception occurs when the compound contains oxygen and chlorine, bromine, or iodine (any halogen except fluorine) in which case oxygen is written last. 2.) If both elements are in the same group, the one closer to the bottom of the table is named first 3.) The Greek name of the second element is given an -ide ending 4.) Greek prefixes indicate the number of atoms of each element. (Exception: The prefix mono- is never used with the first element). When the prefix ends in a or o and the name of the second element is given an -ide ending
What charge of ion does 2A form?
2+ ions
What charge of ion does group 6A form?
2- ions
What is an ionic compound?
A compound that consists of positive and negative ions
What is an anion?
A negatively charged ion
What is a cation?
A positively charged ion
what is the structural formula?
A structural formula shows the atoms carbon by carbon, with the attached hydrogens and functional groups.
Names and Formulas of Ionic Compounds: Anions
A.) the names of monatomic anions are formed by replacing the ending of the name of the element with -ide. A few polyatomic anions also have names ending in -ide which is shown in the pictures B.) Polyatomic anions containing oxygen have names ending in either -ate or -its and are called oxyanions. the -ate is used for the most common or representative oxyanion of an element, and -its is used for an oxyanion that has the same charge but one atom fewer. C.) Prefixes are used when the series of oxyanions of an element extends to four members, as with the halogens. The prefix per- indicates one more O Atom than the oxyanion ending in -ate; hypo- indicates one O atom fewer than the oxyanion ending in -ite. D.) Anions derived by adding H+ to an oxyanion are name by adding s a prefix the word hydrogen or dehydrogenase as appropriate For example: HCO3- is hydrogen carbonate ion or H2PO4- is dehydrogenase phosphate ion.
Names and Formulas of Ionic Compounds: Cations
A.)cations formed from metal atoms have the same name as the metal B.) if a metal can form cations with different charges, the positive charge is indicated by a Roman numeral in parentheses following the the name of the metal - most metals that form cations with different charges are transition metals, elements that occur in the middle of the period table from group 3B to group 2B. The metals that form only one cation are those of group 1A and 2A, as well as Al3+ and two transition metals Ag+ and Zn2+. An older method stills identify used for distinguishing between differently charged ions of metal uses the endings -ous and -ic C.) Cations formed from molecule composed of nonmetal atoms have names that end in -Jim NH4+ is ammonium ion and H3O+ is hydronium ion.
What does group 1A consist of? (Elements and the name)
Alkali metals; Li, Na, K, Rb, Cs, Fr
What does group 2A consist of? (Elements and name)
Alkaline earth metals; Be, Mg, Ca, Sr, Ba, Ra
What s the simplest class of hydrocarbons? And what is carbon bonded to?
Alkanes; each carbon is bonded to four other atoms.
Names and Formulas of Acids
An acid is a substance whose molecules yield hydrogen ions (H+) when dissolved in water. H is the first thing written.
Nonmetal atoms tend to gain elections to form..
Anion
Particles with the same charge repel one another, whereas particles with opposite charges...
Attract one another
What does negative value for the force indicates? What about a positive value?
Attraction ; repulsion
What are metalloids?
B, Si, Ge, As, Sb, Te, At elements that have some properties like metals and some like nonmetals
Ionic compounds tend to be composed of..
Both metal cations and nonmetal anions.
Metal atoms tend to lose electrons to form...
Cations
What does group 6A consist of? (Elements and name)
Chalcogens; O, S, Se, Te, Po
What are hydrocarbons?
Compounds that only contain carbon and hydrogen
What are polyatomic ions?
Consists of atom joined as in a molecules but carrying a net positive or negative charge.
What consists of the coinage metals in group 1B?
Copper (Cu), silver (Ag), and gold (Au). These elements are less reactive than most metals
Who was the one that said the material world is made up of tiny indivisible particles called atomos?
Democritus
What is Coulomb's law?
F= kQ1Q2/d^2 where Q1 and Q2 are the magnitudes of the charges on the two particles, d is the distance between their centers and k is a constant determined by the units for Q and d.
What are the four basic forces known in nature?
Gravitation, electromagnetic, strong nuclear and weak nuclear.
What does group 7A consist of? (Elements and Names)
Halogens; F, CL, Br, I, At
Who is Henri Becquerel?
He discovered that a compound of uranium spontaneously emits high energy radiation
How did Rutherford explain the results of Ernest Marsden's findings?
He explained by postulating the nuclear model of the atom, in which most of the mass of each gold atom and all of its positive charge reside in a very small, extremely dense region called the nucleus. He said that most of the volume of an atom is empty space in which electrons move around the nucleus. Later experiments led to the discovery of positive particles (protons) and neutral particles (neutrons) in the nucleus
Who is J.J Thomson and what did he do?
He observed that cathode rays are the same regardless of the identity of the cathode material. He despicable cathode rays as streams of negatively charged particles that are now called electrons. He constructed a cathode ray tube having a hole in the anode through which the cathode has could pass. Knowing the strengths that resulted in the straight path made it possible to calculate a value of 1.76 x 10^8 coulombs our gram. Not only that but he said that electrons contribute only a very small fraction of an atoms mass. This was called the plum pudding model of the atom.
Who is Ernest Rutherford and what did he do?
He revealed the three types of radiation : alpha, beta, and gamma. He showed that the paths of alpha an beta radiation are bent by an electric field, although in opposite directions; while gamma radiation is unaffected by the field From this he found that alpha and beta rays consist of fast moving electrically charged particles. In fact, beta particles are nothing more than high speed electrons that can be considered the radioactive equivalent of cathode rays. Because of their negative charge, they are attracted to a positively charged place. The alpha particles have a positive charge and are attracted to a negative plate. In the units of the charge of the electron, beta particles have a charge of 1- and alpha particles have a charge of 2+. Not to mention, he suggested that Ernest Marsden look for scattering at large angels which proved there were inconsistencies with Thomas's Plum-pudding model.
Who was Robert Millikan and what did he do?
He succeeded in measuring the charge of an electron by performing the experiment of oil drop experiment to measured the charge of the electron. He then calculated the mass of the electron by using his experimental value for the charge, 1.602 x 10^-19 C and Thomson's charge to mass ratio , 176 x 10^8 C/g
What are periods?
Horizontal rows on the periodic table
What is the lightest atom?
Hydrogen
What elements normally occur as diatomic molecules?
Hydrogen, oxygen, nitrogen, and the halogens (H2, O2, N2, F2, CL2, Br2, and I2).
All elements except for _____ on the left and in the middle are ________
Hydrogen; metallic elements/metals
What is the law of multiple proportions? Give an example:
If two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers. Example: for example, when forming water, 8.0 g of oxygen combines with 1.0 g of hydrogen. In forming hydrogen peroxide, 16.0 g of oxygen combines with 1.0 g of hydrogen. So the ratio of the two compounds is 2:1
What is the law of constant composition?
In a given compound, the relative numbers and kinds of atoms are constant
When did the notion of atoms re-emerges?
In europe during 17th century
What does the prefix "1" in the name 1-propanol indicates?
It incidences that the replacement fo H with OH has occurred at one of the "outer" carbon atoms rather than the "middle" carbon atom.
What is a mass spectrum?
It is a graph of the intensity of the detector signal vs ion atomic mass
What are isotopes? Does isotopes behave alike chemically?
It is atoms with identical atomic numbers but different mass numbers. And yes, they do. For example, a carbon dioxide molecule that contains a 13C atom behaves for all practical purposes identically to one that contains a 12C atom.
WHat is the spontaneous emission of radiation
It is called radioactivity
What is the atomic weight? And why is it important to isotopes?
It is the average atomic mass where the masses of its isotopes are multiplied by their relative abundance's.
What is the law of conservation of mass?
It is the total mass of materials present after a chemical reaction is the same as the total mass present before the reaction
What are functional groups? Give an example
It is when other classes of organic compounds are obtained when one or more hydrogen atoms in an alkane are replaced by specific groups of atoms. For example, an alcohol is obtained by replacing H atom of an alkane with an -OH group.
What do the superscripts +, 2+,3+, etc mean?
It means that a net charge resulting from the loss of one, two, and three electrons
What is the mass spectrometer?
It provides the most accurate means for determining atomic weights.. The first step is to get atoms or molecules int the gas phase. Sometimes, the sample to be analyzed is already a gas, whereas in other cases heating, etc. Next the gas phase societies must be converted to positively charged particles called ions. Once gas phase ions have been produced, they are accelerated toward a negatively charged grid. They are used today to identify chemical compounds and analyze mixtures of substances .
What do the superscript -, 2-, 3-, etc mean?
It represents net charges resulting from the gain of one, two, and thre electrons.
What is the atomic number?
It's the number of protons in an atom for any particular element
Who discovered neutrons?
James Chadwick
How do you predict ionic charges?
Many atoms gain or lose electrons to end up with the same number of electrons as the noble gas closest to them
What properties of alcohols differ from those of the alkanes from which the alcohols are obtained?
Methane, ethane, and propane are all colorless whereas methanol, ethanol, and propanol are color LIQUIDS.
Names and Formulas of Ionic Compounds: Ionic Compounds
Names of ionic compounds consist of the cation name followed by the anion name
Are hydrocarbons named like binary inorganic compounds? If not, how do you name them?
No. Each alkane has a name that ends in -ane. The alkane with four carbon is called butane. For five or more carbons , the names are derived from prefixes. For example, an alkane with eight carbon atoms is octane.
what does group 8A consist of? (Elements and names)
Noble gases; He, Ne. Ar, Kr, Xe, Rn
What is the mass of a proton, neutron, and electron?
Proton: 1.0073 amu Neutron: 1.0087 amu Electron: 5.486 x 10^-4
If an atom has no electrical charge then the number of electrons it contains must equal the number of...
Protons. Example: carbon has atomic number 6 and has 6 protons and 6 electrons.
Who discovered protons?
Rutherford
Explain what cathode rays are
Scientists did a study focusing on electrical discharge through a glass tube pumped almost empty of air. When a high voltage was applied to the electrodes in the tube, radiation (cathode rays) was produced between the electrodes. Cathode rays originated at the negative electrode and traveled to the positive electrodes. Presence of this was detected through light.
An atom is composed of...
Subatomic particles that are the proton, neutrons, and electron
What makes atom of one element different from an atom of another element?
The atoms of each element have a characteristic number of protons.
What is the SI unit for electrical charge?
The coulomb (C)
Writing empirical formulas for ionic compounds
The ions in an ionic compound always occur in such a ratio that the total positive charge equals the total negative charge. The charges on the cation and anion are equal, the subscript on each ion is 1. If the changes are not equal, the charge on one ion will become the subscript for another ion.
What is the molecular formula and empirical formula for H2O2? What about C2H4?
The molecular is H2O2 and the empirical is HO. Molecular is C2H4 and imperial is CH2.
What is the relative size of the atom and its nucleus?
The nucleus is super small and has an incredibly high density.
What are empirical formulas?
The simplest ratio between atoms in a compound
The atomic number is indicated by...
The subscript. The super-subscript is called the mass number, which is the number of protons plus neutrons in the atom.
what a re electromagnetic forces?
They are attractive or repulsive forces that act between either electrically charged or magnetic objects,
Who is Marie Curie and Pierre?
They began experiments to identify and isolate the source of radioactivity in the compound. They concluded that it was the uranium atoms.
What is ozone? And what is the difference between o2 and o3?
Three oxygen atoms bonded together into a single molecule (O3). O2 is essential for life and odorless but o3 is toxic and has a pungent smell
What are groups?
Vertical columns on the periodic table
What is the atomic mass unit (amu)?
Where 1 amu = 1.66054 x 10 ^-24 g.
Some atoms of a given element can differ in the number of neutrons they contain and in mass. What is an example?W
While most atoms of carbon have six neutrons, some have more or less. 12/6C (read carbon 12) reprints the carbon containing six protons and six neutrons, whereas carbon atoms that contain six protons and eight neutrons have a mass number 14, are presented as 14/6C and are referred to as carbon-14.
what are the diameters of an atom?
You use angstrom (A) as a length used for atomic dimensions where 1A = 1 x 10^-10m = 100pm. SO basically, the atoms have diameters of approximately 1-5A (1 x 10^-10 and 5 x 10^-10m)
What is a chemical formula?
a combination of symbols that shows the ratio of elements in a compound
How can you determine Space-filling model?
a model of a molecule showing the relative sizes of the atoms and their relative orientations
What is a diatomic molecule?
a molecule that contains two atoms
what is the periodic table?
an arrangement of elements in columns, based on a set of properties that repeat from row to row
What are molecular compounds? What is an example?
compounds formed from two or more nonmetals. Example: methane consists of one carbon atom and four hydrogen atoms CH4
What are molecular formulas?
give the exact number of atoms of each element in a compound
The ionic compound of Mg (magnesium) and N (nitrogen)
is Mg2+ and N 3- which becomes Mg3N2
What are the three smallest alkanes?
methane, ethane, propane