Chemistry
The emission spectra are obtained due to radiations emitted by excited atoms. The absorption spectra are obtained when atoms absorb energy
Across a period in the periodic table, electronegativity increases from left to right due to a combination of increased nuclear charge and decreasing atomic radius, leading to a stronger attraction for shared electrons.
Electronegativity decreases as you move down a group in the periodic table because the increased atomic size and enhanced shielding effect reduce the nucleus's ability to attract bonding electrons.
Down a group, first ionisation energy generally decreases due to increased atomic size and shielding, causing the outermost electrons to be further from the nucleus and less strongly held.
Across a period, first ionisation energy generally increases due to the increasing nuclear charge and decreasing atomic radius, leading to a stronger attraction between the nucleus and the valence electrons, making them harder to remove.
The definition of First ionisation energy is the minimum energy required to remove the outermost electron from a neutral atom in its gaseous state.
The definition of Electronegativity is the tendency of an atom to bond with another using shared electrons, reflecting its ability to attract electrons in a chemical bond.
Electronegativity is measured from numbers 0-4
Energy levels are called SDPF
Nobel gasses have zero valent electrons
The group number is the same as the number of valence electrons for the main group elements, which determines their chemical reactivity.
Atomic number is Z
Atomic mass is AMU
Neutrons = atomic mass (AMU) - atomic number (Z)
Protons = Atomic number (Z)
Electrons = Atomic Number (Z)
Alpha decay = X ==> Y + 4He
In alpha decay, an alpha particle (2 protons and 2 neutrons) is emitted from the nucleus of an atom, resulting in a new element (Y) with an atomic number reduced by 2.
Alpha decay occurs when the atomic number is greater than 82
Beta Minus decay = X ==> Y + -1e
Beta minus decay occurs when a nucleus is unstable, typically due to an excess of neutrons, leading to the transformation of a neutron into a proton while emitting a beta particle (an electron) and an antineutrino.
Beta plus decay X ==> Y + 1e
Beta plus decay occurs when a nucleus is unstable and transforms into a proton and releases a positron
Atomic Radius decreases across a period
Atomic radius increases down a group
Shielding is when the inner electrons block the attractive force to the outer electrons
The attractive force is the nuclear charge that holds the outermost electrons
Across a period the number of electrons in the same energy levels increase this increases the force of attraction
Across a period the charge of the nucleus increases