U3 Groups and Properties

These flashcards cover key concepts from the Honors Chemistry Unit 3 lecture, including classifications of elements, reactions of metals, and properties of gases.

The physical characteristics of alkali metals including their reactivity with water are __.

Shiny, soft, highly reactive metals that react violently with water.

Alkaline earth metals have __ valence electrons.

Two valence electrons.

Group 1 elements, known as __, are known for their violent reactions with water.

Alkali Metals.

Noble gases are categorized as __ because they typically do not react.

Inert.

The transition metals can lose __ different numbers of electrons.

Different.

Group 17 elements are known as __, which are very reactive nonmetals.

Halogens.

The periodic table is organized into __, which go across and have unrelated characteristics.

Periods.

The elements in the lanthanide and actinide series are considered ___ and ___

mostly radioactive and transition metals

All alkaline earth metals react with oxygen to form __.

Metal oxides.

Transition metals are characterized by having different numbers of __ that they can lose.

Electrons.

Chemical symbols on the periodic table are unique to each __.

Element.

The main group elements include alkali metals, alkaline earth metals, __, and noble gases.

Halogens.

The alkalinity of an alkali metal is defined by its ability to form the negatively charged __ ion in water.

Hydroxide (OH-).

The element Francium is known to be the most __ element in Group 1.

Reactive.

What is atomic radius?

Atomic radius is the distance from the nucleus of an atom to the outermost shell of electrons.

How does atomic radius change across a period on the periodic table?

Atomic radius generally decreases across a period (from left to right) due to an increase in nuclear charge pulling the electrons closer to the nucleus.

How does atomic radius change within a group on the periodic table?

Atomic radius generally increases down a group (from top to bottom) due to the addition of new electron shells, which makes the outermost electrons further from the nucleus.

What is ionization energy?

Ionization energy is the energy required to remove an electron from a gaseous atom or ion.

How does ionization energy change across a period on the periodic table?

Ionization energy generally increases across a period (from left to right) because the increasing nuclear charge and decreasing atomic radius make it harder to remove an electron.

How does ionization energy change within a group on the periodic table?

Ionization energy generally decreases down a group (from top to bottom) because the outermost electrons are further from the nucleus and experience increased shielding from inner electrons, making them easier to remove.

What is an ion?

An ion is an atom or molecule that has gained or lost one or more electrons, resulting in it having a net electrical charge (either positive or negative).

What happens to the radius of an atom when it gains an electron?

When an atom gains an electron to form a negative ion (anion), its radius increases. This is because the added electron increases electron-electron repulsion, causing the electron cloud to expand. Additionally, the effective nuclear charge per electron decreases, allowing the electrons to spread out more.

What happens to the radius of an atom when it loses an electron?

When an atom loses an electron to form a positive ion (cation), its radius decreases. This is because the loss of an electron reduces electron-electron repulsion, and the remaining electrons are pulled closer to the nucleus by the same nuclear charge. Sometimes, an entire electron shell might be removed, leading to a significant decrease in radius.

What is the octet rule?

A chemical rule of thumb that says main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, achieving a stable electron configuration similar to that of noble gases. This tendency leads to the formation of ionic and covalent bonds.

What is electronegativity?

Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself when it is involved in a chemical bond.

What is effective nuclear charge?

The net positive charge experienced by a valence electron from the nucleus, considering the shielding effect of inner-shell electrons which reduce the attraction

How does effective nuclear charge impact atomic radius?

An increase in effective nuclear chargevpulls the valence electrons closer to the nucleus, resulting in a decrease in atomic radius. This is because a stronger positive charge from the nucleus attracts the electron cloud more tightly.

How does effective nuclear charge impact electronegativity?

An increase in effective nuclear charge generally leads to an increase in electronegativity. This is because a stronger positive charge from the nucleus more strongly attracts shared electrons in a bond, making the atom more likely to pull electrons towards itself.

What is electron shielding?

Electron shielding is the effect where inner-shell electrons reduce the effective nuclear charge experienced by outer-shell electrons. The repulsion between inner and outer electrons essentially 'shields' the outer electrons from the full attractive force of the nucleus.

What is paramagnetism?

Paramagnetism is a form of magnetism whereby some materials are weakly ATTRACTED to an externally applied magnetic field. These materials have unpaired electrons, which means they have a net magnetic moment that aligns with the external field.

What is diamagnetism?

Diamagnetism is a form of magnetism whereby some materials are weakly REPELLED by an externally applied magnetic field. These materials have all their electrons paired, meaning they have no net magnetic moment to align with the external field, and instead, induce a magnetic field in the opposite direction.

What is radioactivity?

Radioactivity is the spontaneous emission of radiation from an unstable atomic nucleus. This process occurs as unstable isotopes undergo radioactive decay to transform into more stable forms, releasing energy in the form of alpha particles, beta particles, or gamma rays.