Chem- Ch 4: Atoms and elements

groups

each vertical column

periods

each horizontal row

metals

solids at room temp except mercury, shiny, conduct electricity, are ductile and malleable, form alloys

in chemical reactions, they tend to give up electrons

nonmetals

lie on right side of periodic table, except hydrogen

metalloids

have some properties metals and some of nonmetals, for example, they are shiny like metals, but do not conduct electricity

6 metalloids: boron, silicon, germanium, arsenic, antimony, tellurium

atoms

all elements of the periodic table are made up of atoms, smallest subunit

dalton’s atomic theory

atoms of the same element have the same properties and different elements have different properties

compounds

formed by chemical combos of 2 or more of the same or different kinds of atoms

molecules

tightly bound combo of 2 or more atoms that act as a single unit

law of conservation of matter

matter can neither be created nor destroyed

makeup of an atom

proton- p or p ⁺ , 1+, nucleus

neutron- n, 0, nucleus

electron- e^- , 1^- , outside nucleus

mass #

the sum of the number of protons and neutrons in the nucleus of an atom (protons + neutrons = mass #)

atomic #

the number of protons in the nucleus of an atom, provides the exact identity of an atom (# of protons)

Isotopes

atoms with the same # of protons but a different number of neutrons

atomic weight

the weighted average of the masses (in amu) of the naturally occurring isotopes

electromagnetic radiation

radio we listen to, light waves, microwaves, x rays

Bohrs model

since atoms can only absorb or emit photons at certain energy levels, the levels can be fixed.

electron configuration

describes the “map of an electron arrangement around the nucleus, in each level only certain energies are allowed (1s² , 2s² , 2p⁶ , 3s² , 3p⁶ )

orbital box diagrams

arrows represent electrons

noble gas notation

s orbitals

spheres

p orbitals

shaped like doorknobs, called lobes (2)

d orbitals

shaped like 4 lobes, 1 d orbital is shaped like a donut and a set of lobes

atomic size

the size (radius) of an atom is determined by the radius of its outermost occupied orbitals

Ionization energy

the energy required to remove the most-loosely held electron from an atom in the gaseous state ( increases from left to right and and going up vertically.)