Viewing All Flashcards for Chapter 2: Atoms & the Periodic Table
Questions
1)

- The smallest quantity of matter that still retains the properties of matter
2)

- a substance that cannot be broken down into 2 or more simpler substances by any means Ex: Gold, oxygen, helium

- matter composed of particles- particles called "atomos" (uncuttable)

-1799- Law of definite proportions

-1803- Atomic Theory: a precise definition of the atom

- different samples of a pure chemical substance always contain the SAME PROPORTION OF ELEMENTS by massEx: water always contains 8 g oxygen per 1 gram of hydrogen

- elements are composed of small particles called ATOMS- all atoms of a given element are IDENTICAL (have same size, mass, and chemical properties)- the atoms of one element are DIFFERENT from atoms of all other elements-COMPOUNDS are composed of atoms of more than one element

- REARRANGEMENT- atoms are NOT destroyed or created in chemical reactions

- even smaller particles which give atoms their internal structure (and properties) ~electrons, protons, neutrons
10)

-the emission and transmission of energy in the form of waves

-1895- Rontgen, Bequerel, & M. Curie

- electrons- cathode ray tube experiment

Robert Millikan- oil-drop experiment

- nuclear model- scattering of alpha particles

- positively charged particles (deflected away from positively charged plate)
17)

- negatively charged particles (deflected away from negatively charged plate)

-high energy EM radiation- have no charge and are unaffected by external electric or magnetic fields

9.10 * 10^-28 g

ELECTRONS

Atomic number = number of protons in the nucleus- defines the element- equal to the number of electrons in the atom- determines position in the periodic table

A = total number of protons & neutrons in the nucleusA = Z + (# neutrons)# n's = A-ZA = mass of the atom in amu
23)

- different forms of the same element- the 2 forms have the same # p & e, but DIFFERENT # neutrons-have the same Z but different A- they have the same chemical properties (because properties are determined primarily by # of electrons and protons in the atoms

- average mass

- periodic table

- a chart in which elements have similar chemical and physical properties are grouped together

- arranged by increasing atomic number (Z)

HORIZONTAL rows numbered 1-7

VERTICAL columns containing elements of SIMILAR CHEMICAL PROPERTIES

- the mass of an INDIVIDUAL MOLECULE in atomic mass units (amu)- the SUM of the atomic masses that make up the molecule
31)

1 mol = 6.022 * 10^23 = Avogadro's number = NsubscriptA

The molar mass (M) of anything (molecules, eggs, etc.) is the MASS OF 1 MOLE of that thing in grams.molar mass (g) = molecular mass (amu)

= m/M

= n (Nsubscript A)

M = nM