Untitled Flashcards Set

Atomic Structure:

• Protons: These are found in the nucleus of the atom and carry a positive charge. The number of protons determines the atomic number and the identity of the element.

• Neutrons: Also located in the nucleus, neutrons have no charge but contribute to the mass of the atom. The number of neutrons can vary in the same element, resulting in different isotopes.

• Electrons: These negatively charged particles orbit the nucleus in energy levels or shells. They play a crucial role in chemical reactions and bonding.

Atomic Models:

• Dalton's Solid Sphere Model: Proposed that atoms are indivisible particles, like solid spheres.

• Thomson's Plum Pudding Model: Suggested that atoms consist of a positively charged 'pudding' with negatively charged 'plums' (electrons) scattered throughout.

• Rutherford's Nuclear Model: Revealed that the atom has a small, dense, positively charged nucleus with electrons orbiting around it, suggesting most of the atom is empty space.

• Bohr's Model: Introduced the idea that electrons travel in specific, fixed orbits or shell around the nucleus, with each orbit corresponding to a discrete energy level.

Modern Atomic Model:

• Known as the quantum mechanical model,Let's delve deeper into each concept for a thorough understanding:

Atomic Structure:

• Protons: Found in the nucleus, protons have a positive charge and contribute to the atom's identity. The number of protons is the atomic number, which defines the element.

• Neutrons: Neutral particles also in the nucleus, neutrons add mass to the atom and can vary in number, creating isotopes of an element.

• Electrons: These negatively charged particles orbit the nucleus in energy levels. They are essential for chemical reactions and bonding.

Atomic Models:

• Dalton’s Model: Proposed that atoms are solid, indivisible spheres. This model laid the groundwork for future discoveries.

• Thomson’s Model: Suggested atoms are composed of electrons within a positively charged "soup," often described as a "plum pudding" model.

• Rutherford’s Model: Through his gold foil experiment, Rutherford discovered the nucleus, a dense center of positive charge with electrons orbiting around it.

• Bohr’s Model: Introduced the idea of electrons in fixed orbits or energy levels, explaining atomic emission spectra.

Modern Atomic Model:

• Incorporates quantum mechanics. Electrons are not in fixed paths but in "clouds" or regions where there is a high probability of finding them. This model is more flexible, acknowledging the dual wave-particle nature of electrons.

Periodic Table Organization:

• Periods: Rows across the periodic table. Elements in the same period have the same number of atomic orbitals.

• Groups/Families: Columns down the table. Elements within the same group have similar chemical properties because they have the same number of valence electrons.

Element Categories:

• Metals: Typically found to the left and center of the periodic table. They are good conductors of heat and electricity, malleable, ductile, and tend to lose electrons in reactions.

• Nonmetals: Located on the right side of the table, they are poor conductors and tend to gain electrons in reactions.

• Metalloids: Positioned between metals and nonmetals, metalloids have mixed properties and can conduct electricity under certain conditions.

Valence Electrons and Bonding:

• The valence electrons are the outermost electrons and play a key role in chemical bonding and reactivity.

• Ionic Bonds: Electrons are transferred from one atom to another, resulting in the formation of positively and negatively charged ions.

• Covalent Bonds: Electrons are shared between atoms, allowing them to fill their outer electron shells.