Periodic Table and Atomic Structure Review

Comprehensive question-and-answer flashcards covering periodic families, periodic trends, electron configurations, subatomic particles, and basic chemical principles from the lecture transcript.

How does the group number relate to the number of valence electrons for main-group elements?

The group number relates directly to the number of valence electrons (e.g., Group 2 elements have $2$ valence electrons; Group 15 elements have $5$ valence electrons).

What information does an electron configuration provide, and what does the superscript indicate?

It shows how electrons fill energy sublevels in order ($1s, 2s, 2p, 3s, 3p, 4s, 3d, \text{...}$), where the superscript shows how many electrons are in each sublevel.

What is noble gas shorthand notation?

A notation that replaces the filled inner electron configuration with the symbol of the preceding noble gas in brackets (e.g., $[Ne]3s^2 3p^3$).

What feature of an element matches the row (period) number of the periodic table?

The highest occupied energy level (principal quantum number).

What are Group 1 elements (except hydrogen) called, and what charge do their ions typically carry?

Alkali metals; they are very reactive metals that typically form $1+$ ions.

What are Group 2 elements called, and what charge do their ions typically carry?

Alkaline earth metals; they are reactive metals that typically form $2+$ ions.

What are Group 17 elements called, and what charge do their ions typically carry?

Halogens; they are reactive nonmetals that typically form $1-$ ions.

What are Group 18 elements called, and what is their reactivity and valence shell status?

Noble gases; they are very unreactive (inert) gases with full valence shells.

Where are metalloids located on the periodic table, and what separates metals from nonmetals?

Metalloids form a "staircase" line between metals and nonmetals; elements to the left are mostly metals, and elements to the right are mostly nonmetals.

What are the typical physical properties of metals compared to nonmetals?

Metals tend to be malleable, good conductors of heat/electricity, and have a shiny luster; nonmetals tend to be brittle, poor conductors (insulators), and lack metallic luster.

How does atomic radius change across a period from left to right, and why?

It generally decreases because increasing nuclear charge pulls the valence electrons in closer without adding a new energy level.

How does atomic radius change down a group, and why?

It generally increases because each row adds a new energy level, putting valence electrons farther from the nucleus.

What is the definition of ionization energy?

The energy required to remove the outermost electron from a gas-phase atom.

Why does ionization energy generally decrease down a group?

Valence electrons are farther from the nucleus and shielded by more inner electrons, so they are easier to remove.

What is electronegativity?

An atom's tendency to attract electrons toward itself in a chemical bond.

Which subatomic particle has no electric charge?

Neutron

Who is credited with discovering the nucleus through the gold foil experiment?

Ernest Rutherford

What is the mass number of an atom with $17$ protons and $18$ neutrons?

$$35$$

How do isotopes of the same element differ in subatomic composition?

They always have the same number of protons, but a different number of neutrons.

If an element has two isotopes—one with mass $10$ ($20\%$ abundant) and one with mass $11$ ($80\%$ abundant)—what is the average atomic mass?

$$10.8\,\text{amu}$$

What are the vertical columns of the periodic table called?

Groups or families

What term describes a substance made of two or more elements chemically combined in a fixed ratio?

Compound

Which state of matter has an indefinite shape but a definite volume?

Liquid

What happens to atoms during a chemical reaction?

Atoms are rearranged.

What is a statement that summarizes what has been observed to happen consistently in nature called?

Law

In order of what property does the modern periodic table arrange elements?

Increasing atomic number

What is the net charge of a particle with $11$ protons, $12$ neutrons, and $10$ electrons?

$$+1$$

In isotope notation, what does the subscript number represent?

Atomic number

How many valence electrons does an atom of sulfur (Group 16) have?

$$6$$

What is the noble gas shorthand configuration for nitrogen?

$$[He]2s^2 2p^3$$

Among fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), which element has the largest atomic radius?

Iodine (I)

Which element is a metalloid found along the "staircase" line: sodium (Na), silicon (Si), oxygen (O), or calcium (Ca)?

Silicon (Si)

What are the horizontal rows of the periodic table called?

Periods

Why is ice melting considered a physical change rather than a chemical change?

It is a change in state and not evidence of a chemical change (unlike precipitation, combustion, or rusting).