Chapter 2: Atoms, Ions, and Molecules - Matter Starts Here

Comprehensive practice flashcards covering Chapter 2 concepts including subatomic particles, discovery of the nucleus, isotope calculations, periodic table trends, chemical nomenclature rules, organic functional groups, and nucleosynthesis.

Who discovered the electron in 1897 and what experimental apparatus was used?

J.J. Thomson discovered electrons using a cathode ray tube, observing that the ray was deflected toward a positively charged plate.

What values for an electron's charge and mass were determined by Robert Millikan in 1909?

In his oil-drop experiment, Robert Millikan determined the charge of an electron as $e^- = 1.602 \times 10^{-19}\,C$ and its mass as $9.109 \times 10^{-28}\,g$.

What atomic model proposed by J.J. Thomson is depicted in this image?

The plum-pudding model, which describes electrons distributed throughout a diffuse, positively charged sphere.

How do beta particles and alpha particles differ in composition and charge?

Beta particles ($\beta$) are high-energy electrons, whereas alpha particles ($\alpha$) have a $+2$ charge and a mass equal to a helium nucleus.

Which experiment and scientist are shown in this diagram?

Ernest Rutherford's gold foil experiment, which tested J.J. Thomson's plum-pudding model by bombarding a thin gold foil with $\alpha$ particles.

How did James Chadwick discover the neutron?

He bombarded a thin sheet of beryllium with $\alpha$ particles, causing the emission of uncharged high-energy radiation composed of neutral subatomic particles called neutrons.

How is an atomic mass unit (amu) defined?

An atomic mass unit (amu or Da) is defined as equal to $1/12$ of the mass of a carbon atom ($1\,\text{amu} = 1\,\text{Dalton}$).

What experimental instrument and findings are shown in this figure?

Francis Aston's positive-ray analyzer, which demonstrated the existence of neon isotopes ($20\,\text{amu}$ and $22\,\text{amu}$) by deflecting $Ne^+$ ions using electric and magnetic fields.

In the nuclide notation ${_Z^A}X$, what do $A$, $Z$, and $X$ represent?

$A$ represents the mass number (total protons + neutrons), $Z$ represents the atomic number (number of protons), and $X$ represents the elemental symbol.

How is the average atomic mass of an element calculated?

It is calculated by multiplying the natural abundance of each isotope (expressed as a decimal fraction) by its atomic mass in amu, and then summing these products.

How did Dmitri Mendeleev construct his early periodic table?

Dmitri Mendeleev ordered elements by atomic mass, arranged them in columns based on similar physical and chemical properties, and left open spaces for undiscovered elements.

What are the group names for Group 1, Group 2, Group 17, and Group 18 in the periodic table?

Group 1: Alkali metals; Group 2: Alkaline earth metals; Group 17: Halogens; Group 18: Noble gases.

What is the Law of Multiple Proportions?

It states that the ratio of the masses of one element that combine with a fixed mass of another element to form two different compounds is a ratio of small whole numbers.

What is the difference between a molecular formula and an empirical formula?

A molecular formula shows the exact number and type of atoms present in one molecule of a compound, whereas an empirical formula shows the smallest whole-number ratio of elements.

How do the Classical system and Stock system differ when naming transition metal ions?

The Classical system uses Latin root names with suffixes (-ous for lower charge, -ic for higher charge), while the Stock system uses the element's English name followed by a Roman numeral in parentheses equal to the charge.

How do prefixes and suffixes indicate the number of oxygen atoms in chlorine oxoanions?

$ClO_4^-$ is perchlorate (one more oxygen than chlorate), $ClO_3^-$ is chlorate, $ClO_2^-$ is chlorite (one less oxygen than chlorate), and $ClO^-$ is hypochlorite (one less oxygen than chlorite).

How do the names of oxoacids relate to the names of their corresponding oxoanions?

If the oxoanion name ends in -ate, the corresponding acid name ends in -ic acid. If the oxoanion name ends in -ite, the corresponding acid name ends in -ous acid.

What structural feature distinguishes alkanes, alkenes, and alkynes?

Alkanes contain only single carbon-carbon bonds, alkenes contain one or more carbon-carbon double bonds ($C=C$), and alkynes contain one or more carbon-carbon triple bonds ($C \equiv C$).

What process is depicted in this stellar core model?

Stellar nucleosynthesis, where high temperatures and densities inside stars drive nuclear fusion to produce shells of heavier elements (such as $3\,{^4_2He} \rightarrow {^{12}_6C}$) up to an iron ($Fe$) core.