NUCLEAR ATOM Flashcards
Ions
Charged particles that are formed when an atom loses or gains an electron (diff no. of electrons)
Cation - positive ion (formed when atoms lose electrons)
Anion - negative ion (formed when atoms gain electrons)
Isotopes
Different atoms of the same element with different mass numbers (same no. of protons, diff no. of neutrons)
They have the same chemical properties but different physical properties (diff melting and boiling points)
Reason: Isotopes have the same chemical properties as they have same number of electrons (and chemical reactions depend on the number of electrons), but different physical properties as they have different mass numbers
Ionic radius
Greater ionic radius:
Smaller number of protons, attracts electrons less effectively (reason: the more protons there are, the stronger the attraction bond)
Suggest two reasons why atoms are no longer regarded as the individual units of matter
- Atoms can be broken down/split into protons, neutrons and electron
- atoms can gain/lose electrons
- existence of isotopes
Mass spectrometry
Mass spectrometry is an analytical tool useful for measuring the mass-to-charge ratio (m/z) of one or more molecules present in a sample.
First ionisation energy
Amount of energy needed to remove 1 mole of electrons from 1 mole of gaseous atoms to form one mole of singly charged positive ions in the gaseous state
Define relative atomic mass (Ar)
It is the average mass of an atom of an element compared to 1/12 to the mass of an atom of carbon-12
Atoms
Consist of a central positively charged nucleus made up of protons and neutrons, where most of the mass is concentrated. The negatively charged electrons occupy the space outside the nucleus.
Protons and neutrons, the particles that make up the nucleus, are called the nucleons.
Atomic number (Z)
No. of protons in the nucleus of an atom
No. of electrons = No. of protons = Atomic number
Mass number (A)
Total number of protons + neutrons in the nucleus of an atom
No. of neutrons = mass no. - atomic no.
