Name Block Date Ch 17 Atomic Nature of Matter Notes Mrs. Peck atoms- the smallest particle of an element that can be identified with that element are the building blocks of matter consists of protons and neutrons in a nucleus surrounded by electrons element-a substance made of only one kind of atom atoms of the same kind make up an element atoms w/ same # of protons belong to same element atoms w/ diff. # of protons are different elements 115 elements known today 90 elements occur in nature, rest made in laboratory with high-energy accelerators and nuclear reactors [ these are too unstable (radioactive) to occur naturally ] 99% of material on Earth is formed from only about a dozen elements Living things: composed primarily of 6 elements CHNOPS carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P), sulfur (S) organism-cells-molecules & compounds-atoms- 1)nucleons: protons & neutrons 2)electrons hydrogen- the lightest of all elements most abundant element in universe (90% of all atoms are H) helium- second lightest element makes up most of the remaining atoms in universe rare on Earth TABLE 17.1 pg 245 most common elements and their symbols Element is represented by a symbol. mass # charge consists of 1 or 2 letters. 1st- capitalized 2nd- lower case Symbol atomic # eg. atoms are recyclable: they cycle & recycle among numerous forms: both living & nonliving Atoms are very small smaller than wavelength of visible light, so can not see them with a compound light microscope
Atoms are constantly moving...add heat...adds E...atoms move faster... phase 2 solid: low rate of movement liquid: more movement gas: highest rate of movement molecule or compound two or more atoms of the same or different elements bonded to form a larger particle matter that is a gas or liquid at room temperature is usually made of molecules there is a limited number of different atoms, but there are many different molecules molecules & compounds have different properties from the elements which they are made eg: oxygen or nitrogen gas O2 N2 methane gas CH4 water H2O is a molecule table salt (sodium chloride) NaCl is a compound Chemical formula- a description that uses numbers and symbols of elements to describe the proportions of elements in a compound or reaction. represented using element symbols a subscript number directly after the symbol indicates the # of atoms of that element If there is only one atom of an element then the number 1 is omitted and understood ex. H2SO4 Na3PO3 C6H12O6 CaCl sulfuric acid consists of 2 hydrogen atoms, 1 sulfur atom, 4 oxygen atoms sodium phosphate has 3 sodium atoms, 1 phosphorus atom, 3 oxygen atoms glucose has 6 atoms of carbon, 12 atoms of hydrogen, 6 atoms of oxygen calcium chloride has 1 atom of calcium and 1 atom of chloride
3 atom- has a nucleus in the center (protons& neutrons) w/ electrons orbiting around nucleus nucleus-the positively charged center of an atom contains nucleons: protons and neutrons has almost all the mass of the entire atom but only a tiny fraction of the volume the center mass filled region of an atom very compact and dense, nucleus small compared to the actual size of the atom nucleons- the principal building block of the nucleus: proton and neutron neutron- an electrically neutral particle that is one of the two kinds of particles that compose an atomic nucleus all neutrons are identical proton- a positively charged particle that is one of the two kinds of particles found in the nucleus of an atom all protons are identical atoms of different elements differ from one another by their atoms with the same number of protons all belong to the same if an atom has a different # of protons then Atomic number- number of protons in the nucleus of an atom elements are organized in the periodic table by their atomic number eg. hydrogen- has 1 proton...atomic number is 1 helium- has 2 protons...atomic number is 2 lithium- has 3 protons...atomic number is 3 PEA- # protons = # electrons = atomic number (atoms with no charge except for ions) Atomic mass number- total number of nucleons (neutrons & protons) in the nucleus of an atom
4 atom- has a nucleus in the center (protons and neutrons) with electrons orbiting around nucleus at different levels (shells) electrons are negatively charged particles that orbit around the nucleus electrons are very small& do not significantly contribute to the atomic mass of atom mass of electron is small compared to mass of a nucleon in a electrically neutral atom: the number of electrons equals the number of protons shell model of the atom- a model in which the electrons of an atom are grouped in concentric shells around the nucleus electrons are believed to be orbiting in spherical shells around the nucleus (it is actually more complicated there are 7 shells 1st can hold up to 2 e - 2nd can hold up to 8 e - 3rd can hold up to 18 e - electron configuration / arrangement of electrons *it is the electrons in the outer shell that dictate the bonding properties and chemical properties of an element such as melting point, taste, color, ect. determines how element with react or bond with other elements or atoms
for a given element: the number of protons never changes 5 the number of protons equals number of electrons (neutral atom) the number of neutrons will vary...mass will vary...isotope isotope- a form of an element having a particular number of neutrons in the nuclei of its atoms. Different isotopes of the same element have 1. same atomic number (same # protons) 2. different atomic mass numbers (mass = # protons + # neutrons) isotope: atoms of the same element having same number of protons and different numbers of neutrons...varying the atomic mass every element has a variety of isotopes eg. carbon 12 C has 6 protons and 6 neutrons...mass number=12 14 C has 6 protons and 8 neutrons...mass number =14
ion- atom or group of atoms with a net electric charge, due to the loss or gain of electrons 6 when the number of electrons is more or less than the number of protons in an atom ion has a net charge: positive if the number of electrons is less than the number of protons eg. Na +, K +, Ca +2 these atoms have 1 or 2 more protons than e - negative if the number of electrons is more than the number of protons eg. Cl -, Br - these atoms have 1 more e - than protons Bonding: attraction between a proton and an electron can cause a bond between atoms to form a molecule electrons can be transferred between two atoms to form a bond between 2 atoms 2 types of bonding: 1. ionic bonding- one atom gives up electron(s) and one atom gains electron(s 2. covalent bonding-electrons are shared between two atoms
Neutral atom 9 P 10 N 7 19 element fluorine symbol F 9 Atomic # 9 protons 9 mass # 19 nucleons 19 neutrons 10 electrons 9 charge 0 Isotope 14 element carbon symbol C 6 6 P 8 N Atomic # 6 protons 6 mass # 12 nucleons 14 neutrons 8 electrons 6 charge 0 isotope 14 C Ion 17 P 18N 35-1 element chlorine symbol Cl 17 Atomic # 17 protons 17 mass # 35 nucleons 35 neutrons 18 electrons 19 charge -1 isotope no
periodic table- a chart that lists elements by atomic number and by electron arrangements, 8 so that elements with similar chemical properties are in the same column from left to right: each element has one more proton & electron than the preceding element elements that are side by side the atomic # increases from left to right and from top to bottom the atomic mass generally increases from left to right and from top to bottom metals: elements to the left of the heavy line running stepwise from boron to astatine malleable, conduct electricity & heat nonmetals:elements to the right of the heavy line running stepwise from boron to astatine non conductors, at room temp- gas or liquid, non-reflective period- elements in the same row in periodic table, they have same number electron shells as period number eg. period 1: is 1st row, elements have electrons only in 1st shell period 2: is 2nd row, elements all have electrons in 1st and 2nd shell only as you go down a column, each element has one more shell filled to its capacity in each period, as the atomic number increases in the period, the elements generally change from very active metals, to less active metals, to metalloids, to less active nonmetals, to very active nonmetals Group-elements in the same column in periodic table, they have similar chemical properties and react with other elements in the same way to form new compounds because their outermost electrons are arranged the same way group 1 group 2 group 3-12 group 7 group 8 alkali metals alkaline earths transitional metals other metals metalloids non-metals halogens noble gases elements tend to form ions by borrowing or lending electrons to produce the electron configuration-arrangement of the nobel gas closest in atomic number this is the magic rule of 8 (or 2)
Phases of Matter 9 in all phases of matter the atoms are constantly in motion Atoms are constantly moving...add heat...adds energy...atoms move faster...change phase solid: low rate of movement liquid: more movement gas: highest rate of movement 4 phases: solid: atoms and molecules vibrate about a fixed position liquid: increased molecular motion, the molecules move in non fixed position & take on the shape of its container molecules flow freely from postion to position sliding over one another. is a fluid- anything that flows take on shape of its container gas: increased energy causes molecules to move about at higher rates & break away from each other molecules are far away from each other, enabling continuous movement, they will periodically have elastic collisions with not net change in Energy is a fluid- anything that flows take on shape of its container primary difference b/w liquid and gas: is the distance b/w molecules due to the E that the molecules have. plasma: exists mainly at extremely high temperatures (2000 C ) matter consists of positively charged ions and free electrons matter consists of positive ions (atoms that are missing some electrons) and free electrons predominant phase of matter in the universe such as in stars