Chapter 2 Content Flashcards
Accoriding to the atomic theory by John Dalton, what happens to atoms when undergoing a chemical reaction?
- in a chemical reaction, atoms are neither created nor destroyed they just rearrange
What does the law of consveration of matter state?
it states that matter can neither be created nor destroyed (instead its rearranged in chemical reactions)
What does the law of conversation of mass-energy state?
it states that while the total mass and energy of a system is conserved, mass and energy can interconvert
What are the 3 subatomic particles and what are their characteristics?
Protons:
- are considered a massive particle because they have a significant mass
- have a positive charge in a nucleus
Neutrons:
- are considered a massive particle because they have a significant mass
- have a neutral charge in a nucleus
Electrons:
- are not considered a massive particle because they have a practically insignificant mass
- have a negative charge and orbit AROUND a nucleus
What was Rutherford’s big breakthrough?
his breakthrough was to attempt to confirm the plum-pudding model
What are alpha particles?
alpha particles are radioactive particles with a positive charge, high energy, and a significant mass
What were the 2 main conclusions of Rutherfords’ experiment?
1) the atom is mostly empty spaced
2) something with a positive charge and relatively large mass occupies a small volume within the atom (nucleus)
What determines the identity of an atom?
the identity of an atom is determined by the number of protons (atomic number = number of protons)
What is an isotopes mass number?
an isotopes mass number is the sum of its number of protons and neutrons
- Mass number= #p + #n *
What is an isotope’s percent natural abundance?
an isotopes percent natural abundance is a measure of the average amount the isotope naturally occurs relative to all of the element’s isotopes
Where does an elements atomic mass come from?
an elements atomic mass is a weighted average of all the masses of its naturally occurring isotopes
What are ions?
Ions are charged versions of atoms (altered # of electrons)
What makes a cation?
atoms lose electrons to become positively charged ions (makes a cation); cations have an excess of protons
What makes an anion?
atoms gain electrons to become negatively charged ions (makes an anion); anions have an excess of electrons
What are the names of groups 1,2,5,6,7,8 in the periodic table?
group 1 = alkali metals
group 2 alkaline earth metals
group 5 = pnictogens
group 6 = chalcogens
group 7 = halogens
group 8 = noble gases
