Atoms, Molecules, and Ions

Flashcards covering Dalton's Atomic Theory, atomic structure, the periodic table, types of molecules and ions, chemical formulas, and nomenclature for ionic and molecular compounds.

What are the fundamental building blocks of matter discussed in chemistry?

Atoms, Molecules, and Ions.

According to Dalton's Atomic Theory, what are elements composed of?

Extremely small particles called atoms.

How do atoms of a given element compare to each other, and to atoms of other elements, according to Dalton?

All atoms of a given element are identical in size, mass, and chemical properties, but different from atoms of all other elements.

How does Dalton's theory describe the composition of compounds?

Compounds are composed of atoms of more than one element, with the ratio of atoms of any two elements being an integer or simple fraction.

What happens to atoms during a chemical reaction, according to Dalton's Atomic Theory?

A chemical reaction involves only the separation, combination, or rearrangement of atoms, not their creation or destruction.

Which law states that matter can neither be created nor destroyed in a chemical reaction?

The Law of Conservation of Mass.

What does the Law of Multiple Proportions state regarding two elements forming a compound?

If two elements form a compound, then the ratio of the mass of the second element to the mass of the first element will be small whole number ratios.

What was the key feature of Thomson's atomic model?

It proposed that positive charge was spread over an entire sphere, with electrons embedded within it.

What did Rutherford's experiment conclude about the positive charge of an atom?

The atom's positive charge is concentrated in a dense central region called the nucleus.

What is the charge relationship between a proton and an electron?

A proton has an opposite (+) charge to an electron (-).

How does the mass of a proton compare to the mass of an electron?

The mass of a proton is approximately 1840 times the mass of an electron.

How does the atomic radius compare to the atomic nucleus radius in Rutherford's model?

The atomic radius (~100 pm) is significantly larger than the atomic nucleus radius (~5 x 10^-3 pm).

Who discovered the neutron?

J. Chadwick.

What is the charge of a neutron?

A neutron is neutral (charge = 0).

How does the mass of a neutron compare to the mass of a proton?

The mass of a neutron is approximately equal to the mass of a proton.

What is the charge of an electron and who discovered it?

Negative (-1), discovered by J. J. Thomson.

What is the charge of a proton and who discovered it?

Positive (+1), discovered by Ernest Rutherford.

What is the charge of a neutron and who discovered it?

Neutral (0), discovered by J. Chadwick.

What is the atomic number (Z) of an element?

The number of protons in the nucleus.

What is the mass number (A) of an atom?

The sum of the number of protons and neutrons (atomic number + number of neutrons).

Which subatomic particles are the only ones that have a charge?

Protons and electrons.

In a neutral atom, how does the number of protons relate to the number of electrons?

The number of protons equals the number of electrons.

What are isotopes?

Atoms of the same element with different masses, meaning they have different numbers of neutrons.

How many protons, neutrons, and electrons are in Carbon-14 (C-14)?

6 protons, 8 neutrons (14-6), and 6 electrons.

The nucleus of an atom contains which subatomic particles?

Protons and neutrons.

Atoms with identical atomic numbers but different mass numbers are called what?

Isotopes.

How are elements arranged in the modern periodic table?

In order of increasing atomic number.

What are the horizontal rows in the periodic table called?

Periods.

What are the vertical columns in the periodic table called, and what do elements in them typically share?

Groups or families; elements in the same group have similar properties.

Which elements are good conductors of heat and electricity?

Metals.

What are metalloids, and what are their properties like?

Metalloids have properties that are intermediate between metals and nonmetals.

What are the common names for Group 7A and Group 8A elements?

Group 7A: Halogens; Group 8A: Noble Gases.

Selenium (34Se) is what type of element and in which group is it found?

It is a nonmetal and found in group 6A.

Which set of elements is expected to have similar chemical properties: Sulfur and phosphorous, Sulfur and oxygen, or Sulfur and argon?

Sulfur and oxygen (because they are in the same group).

Which element is most likely to be a good conductor of electricity among N, S, He, Fe?

Fe (Iron) because it is a metal.

Gallium (Ga) is found in which period and group of the periodic table?

Period 4, group 3A.

What is a molecule?

An aggregate of two or more atoms in a definite arrangement held together by chemical forces.

What defines a diatomic molecule, and can you give an example?

A diatomic molecule contains only two atoms, e.g., H2, O2, HCl.

What defines a polyatomic molecule, and can you give an example?

A polyatomic molecule contains more than two atoms, e.g., O3, H2O, CH4.

What is an ion?

An atom, or group of atoms, that has a net positive or negative charge.

What is a cation, and how is it formed from a neutral atom?

A cation is an ion with a positive charge, formed when a neutral atom loses one or more electrons.

What is an anion, and how is it formed from a neutral atom?

An anion is an ion with a negative charge, formed when a neutral atom gains one or more electrons.

A magnesium ion, Mg2+, has how many protons and electrons?

12 protons and 10 electrons.

A sulfide ion, S2-, has how many protons and electrons?

16 protons and 18 electrons.

What is a monatomic ion, and can you give an example?

A monatomic ion contains only one atom, e.g., Na+, Cl-.

What is a polyatomic ion, and can you give an example?

A polyatomic ion contains more than one atom, e.g., NH4+, OH-.

How many protons and electrons are in Al3+?

13 protons, 10 electrons (13 - 3).

How many protons and electrons are in Se2-?

34 protons, 36 electrons (34 + 2).

Which is an example of a polyatomic cation: Mg2+, NH4+, O2-, SO4 2-?

NH4+.

Which is an example of a monatomic anion: Mg2+, NH4+, O2-, SO4 2-?

O2-.

What information do molecular formulas provide?

The actual numbers and types of atoms in a molecule.

What information do empirical formulas provide?

The simplest whole number ratio of the atoms in a molecule.

What is the empirical formula for Acetylene (C2H2)?

CH.

What is the empirical formula for Caffeine (C8H10N4O2)?

C4H5N2O.

Which of the following is an empirical formula: O3, H2SO4, S8, C6H12O6?

H2SO4.

Which of the following is a molecular formula (can be simplified): CO2, H2SO4, S8, CH4O?

S8.

How many protons, neutrons, and electrons are there in Mg2+?

Protons = 12, Neutrons = 12 (24-12), Electrons = 10 (12-2).

What is the empirical formula for Butane (C4H10)?

C2H5.

Which of the following is an example of a mono-atomic cation: Mg2+, NH4+, O2-, NO3-?

Mg2+.

What are ionic compounds composed of?

A combination of cations and anions.

What types of elements typically combine to form ionic compounds?

The most reactive metals and the most reactive nonmetals.

What is the formula for Zinc iodide?

ZnI2.

What is the chemical formula for Aluminum oxide?

Al2O3.

What is the chemical formula for Sodium carbonate?

Na2CO3.

How are fixed-charge metal cations named?

The name of the metal cation is the same as the metal element's name (e.g., silver ion, zinc ion).

How are variable-charge metal cations named?

The charge is indicated by a Roman numeral in parentheses after the metal name (e.g., iron(II), copper(I)).

Can you name the polyatomic cation NH4+?

Ammonium.

What is unique about the formula for mercury(I) cation?

It is Hg2 2+ (mercury(I) or mercurous), not Hg+.

How are monatomic anions named?

The ending of the element name is changed to "-ide" (e.g., Oxide, Chloride).

What are common endings for polyatomic anions, and what elements do they usually contain?

Most end in "-ate" or "-ite" and usually contain oxygen.

What is the name of the anion NO3-?

Nitrate.

What is the formula for a hydroxide ion?

OH-.

When is a Roman numeral used in the name of an ionic compound?

Only if the metal has a variable charge.

How do you name FeCl2?

Iron(II) chloride.

How do you name Cr2S3?

Chromium(III) sulfide.

Name (NH4)3PO4.

Ammonium phosphate.

Name Cu(NO3)2.

Copper(II) nitrate.

Write the chemical formula for Mercury(I) nitrite.

Hg2(NO2)2.

Write the chemical formula for Calcium phosphate.

Ca3(PO4)2.

What types of elements form molecular compounds?

Nonmetals or nonmetals + metalloids.

What are the three steps for naming binary molecular compounds?

1) Name the first element with a prefix indicating the number of atoms. 2) Name the second element with a prefix for the number of atoms. 3) Change the ending of the second element to "-ide".

How do you name PCl5?

Phosphorus pentachloride.

How do you name CO?

Carbon monoxide.

When is the "mono-" prefix never used for the first element in a molecular compound name?

When there is only one atom of the first element.

What happens to the ending "a" or "o" in a prefix when naming oxides?

The ending "a" or "o" is omitted (e.g., dinitrogen tetroxide, not tetraoxide; dinitrogen monoxide, not monooxide).

Write the formula for Diphosphorus pentasulfide.

P2S5.

Write the formula for Dinitrogen pentoxide.

N2O5.

Which pair of elements would be most likely to form an ionic compound: P and Br, Cu and K, C and O, O and Zn, Al and Rb?

O and Zn.

Which pair of elements would be most likely to form a molecular compound: Na and Br, C and O, Ca and O, Zn and O, Mg and Cl?

C and O.