Periodic Table and Atomic Trends

Comprehensive review flashcards covering periodic trends, element classifications, Coulomb's Law, electronic configurations, and properties of metals, nonmetals, and metalloids.

Russian chemist __________ is credited with being the first scientist to arrange elements in a usable table ordered by increasing atomic mass.

Dmitri Mendeleev

English scientist Henry Moseley used X-rays to establish that elements in the modern Periodic Table should be arranged in order of increasing __________.

atomic number

The Periodic Law states that the physical and chemical properties of elements are periodic functions of their __________.

atomic numbers

On the Periodic Table, horizontal rows are called __________ and vertical columns are called groups or families.

periods

The number at the beginning of each period indicates the __________ where valence electrons are located for atoms in that row.

energy level

Elements within the same group share similar chemical properties and react similarly because they possess the same number of __________.

valence electrons

Approximately __________ of all elements on the Periodic Table are classified as metals.

$$\frac{2}{3}$$

Although they directly border the zigzag staircase line on the Periodic Table, aluminum and __________ are exceptions classified as metals rather than metalloids.

polonium

The elements highlighted along the staircase line (boron, silicon, germanium, arsenic, antimony, and tellurium) are classified as __________.

metalloids

On the Periodic Table, the most reactive metal is francium, whereas the most reactive nonmetal is __________.

fluorine

The only two elements that exist in the liquid state at standard temperature and pressure (STP) are mercury and __________.

bromine

Elements located in Groups $3$ through $12$ are called transition elements, which often have multiple oxidation states and form compounds that produce a distinct __________ in solution.

color

Group $17$ (the halogens) is unique because it is the only group on the Periodic Table that contains elements existing in all __________ phases of matter at room temperature.

$$3$$

Two or more forms of the same element that have different molecular structures and different chemical properties, such as $O_2$ and $O_3$, are called __________.

allotropes

In the carbon allotrope known as __________, every carbon atom is covalently bonded to four other carbon atoms in a rigid network, whereas graphite consists of planar sheets.

diamond

A neutral atom has an equal count of protons and electrons, while a positively charged ion, known as a __________, is formed when a metal atom loses valence electrons.

cation

Atomic radius is defined as the distance from the atomic nucleus to the __________ shell of electrons.

outermost

Atomic radius increases as you move down a group primarily because the total number of occupied __________ increases.

principal energy levels

Atomic radius decreases as you move left to right across a period because an increasing number of __________ in the nucleus pulls the valence shell closer.

protons

According to Coulomb's Law, when the distance ($d$) between the valence electrons and the positive nucleus increases, the force of attraction ($F$) __________.

decreases

The amount of energy required to remove an electron from an atom in the ground state is known as __________ energy.

ionization

Moving left to right across a period, first ionization energy generally __________ because the increasing nuclear charge binds valence electrons more tightly.

increases

The measure of an atom's ability to attract electrons in a chemical bond is termed __________.

electronegativity

When a nonmetal atom gains electrons to achieve an octet, its ionic radius becomes __________ than its original neutral atomic radius.

larger

During the formation of a sodium ion ($Na^+$) from a sodium atom ($Na$), the ionic radius decreases because the atom loses its outermost electron along with an entire __________.

electron shell

In a Lewis electron-dot diagram of an anion, the chemical symbol is enclosed in brackets showing a complete octet of __________ valence electrons with the charge outside.

$$8$$

Potassium reacts significantly more vigorously with water than lithium because potassium has a larger atomic radius, resulting in a __________ Coulombic force holding its outermost valence electron.

weaker

An excited-state atom possessing the electron configuration $2\text{-}8\text{-}7\text{-}1$ has a total of $18$ electrons, which corresponds to the element __________.

argon

When an excited valence electron transitions down to a lower principal energy level, it emits a photon whose frequency is __________ proportional to its wavelength.

inversely