Chemistry - trends test

Alkali

group 1 - s1 block - do not exist in the pure form in nature

Alkali Earth Metals

group 2 - s2 block - do not exist in the pure form in nature

Transition Metals

all have s2 valance configuration except special columns - less reactive

What are salts?

cations (+) bonded to anions (-)

Noble gas

group 18 - non reactive in nature b/c they have 8 valence electrons or an octet

Halogens

group 17 - most reactive nonmetals b/c they need one electron to form an noble gas configuration

Lanthanides

4f - elements with atomic numbers from 58-71 (inner transition)

Actinides

5f - elements with atomic number from 90-103 (inner transition)

The atomic radii (increases, decreases) down a column. Why?

Increases - As you go down a column, zeff is relatively constant, but the outermost electrons are placed in higher values on n (higher energy levels)

The atomic radius (increases, decreases) down a row. Why?

Decreases - As we go across the row, zeff goes up which pulls in the outermost electron causing the atomic radius to go down.

Ionization energy

Defined as the energy required to REMOVE an electron from an atom which is an ENDOTHERMIC process. This will form a cation, which is a positively charged ion.

Ion

an atom or group of atoms that has a positive or negative charge due to the gain or loss of electrons

Ionization

process of forming an ion

The ionization energy (increases, decreases) across a row. Why?

Increases - As we go down row, zeff goes up causing the atomic radius to go down, which takes more energy to remove valence electrons due to strong attractive forces.

The ionization energy (increases, decreases) down a column. Why?

Decreases - As we go down a column, electrons are in higher energy levels and experience weaker attractive forces. Shielding also plays a role

Shielding

inner electrons blocking outer electrons from feeling the full positive pull of the nucleus

What is the connection between atomic radius and ionization energy?

As atomic radius goes down, attractive forces increase, making ionization energy also increase

Zeff

attractive force that is exerted on an atoms valance electrons by the nucleus z-s

z = charge of nucleus (#p)

s = screening constant (# of inner electrons)

Row trend

As we go across a row, zeff increases, due to more protons being added to the nucleus and screening electrons staying constant

Column trend

In reality, zeff increases slightly down a column, but now enough to make a significant difference