Understanding Elements and the Periodic Table

ELEMENT: A substance formed by atoms that are equal, e.g., we take a piece of earth; all Fe atoms are equal. All the elements are in the periodic table. Compounds are formed when different atoms combine with each other, e.g., water (H₂O) -> H₂O. Each symbol is assigned to make it easier to study.

PERIODIC TABLE

1. Elements are sorted in increasing order of their atomic number.
2. Elements in the same period have the same energy levels or layers of electrons.
3. Elements that have the same last level of electrons and similar chemical properties are located in the same vertical group.

There are 7 periods. The groups coincide in addition to having the same number of electrons in the outer shell. The classification of the outer electrons is important for metals, nonmetals, and metalloids. The further to the left you go down a group, the more metallic the element becomes. The most metallic element is Francium (Fr).

Metal and Nonmetal

An element is more metallic than another when it can lose an electron more easily. The farther an electron is from the nucleus, the less energy is required to remove it from the outer shell.

FEATURES:

• Metals have a characteristic brightness.
• Nonmetals are poor conductors of heat and electricity.
• Metals can be stretched and shaped, while nonmetals are fragile and can break easily.
• Except for mercury, which is a liquid metal, all other metals are solids at room temperature (approximately 25ºC).

GROUPS OF ELEMENTS:

1. Isolated Atoms: Noble gases (Group 8A) such as He, Ne, etc., have 8 electrons in their outer shell and do not form compounds because their structure is stable.

2. Forming Diatomic Molecules: A molecule is formed when 2 equal atoms bind together through weak forces; all are gases at room temperature.

3. Forming Crystals:

Non-Metallic Crystals:

A crystal is a three-dimensional network of atoms bonded to each other that are not metals.

Metal:

Metals can release one or two electrons, forming a lot of positive ions surrounded by a sea of electrons.