Chapter 16 Flashcards
how do the number of valence electrons determine the reactability of an element?
if an atom’s outer layer is full, reactions will occur less often/not at all between that atom and other atoms.
a diagram that uses the chemical symbol of an element surrounded by dots to represent the number of electrons in the outermost energy level
electron dot diagram
what kind of electrons determine the chemical properties of each individual element?
valence electrons
electrons in the outermost energy level of an atom
valence electrons
the vertical columns in the periodic table are called
groups (or families)
the horizontal rows of elements in the periodic table
periods
elements in the same group on the periodic table have (similar/different) chemical properties
similar
a table that arranges elements by increasing atomic number, not atomic mass, and by periodic changes in physical and chemical properties.
periodic table
chlorine has an average atomic mass of 35.45 amu. the two naturally occurring isotopes of chlorine are chlorine-35 and chlorine-37. do most chlorine atoms contain 18 neutrons or 20 neutrons? why?
most chlorine atoms contain 18 neutrons. there are 17 protons in chlorine, and because the average atomic mass is closer to 35, more chlorine atoms have a mass number of 35.
explain how the isotopes of an element are alike and how they are different.
isotopes of an element are alike in the ways that they have the same number of protons, but different numbers of neutrons, causing different mass numbers between them (meaning isotopes)
calculate the average atomic mass in amu of boron-10 and boron-11:
4/5(11 amu) + 1/5(10 amu) = ?
10.8 amu
the weighted average mass of all naturally occurring isotopes of an element, measured in atomic mass units (amu), according to their natural abundances
average atomic mass
atoms of the same element that have different numbers of neutrons
isotopes
the sum of the number of protons and the number of neutrons in the nucleus of an atom
mass number
the number of protons in an atom’s nucleus
atomic number
protons and neutrons are over ____ times more massive than electrons
1,800
the approximate size of protons and neutrons
1.67 * 10^-24
why is the electron cloud the most accurate to date
electrons move so quickly and randomly that it is impossible to exactly pinpoint its exact location at any given moment
state the terms of dalton’s atomic theory
- matter is composed of atoms
- atoms are indivisible and indestructible (disproven)
- atoms of a given element are identical in size, mass, and chemical properties
- atoms of a specific element are different from those of another element
- different atoms combine in simple whole-number ratios to form compounds
- in a chemical reaction, atoms are separated, combined, or rearranged.
name the five atomic models and their approximate dates
400 B.C. – Democritus Model
1904 – Thomson Model
1911 – Rutherford Model
1913 – Bohr Model
1926 – Electron Cloud Model
how are quarks discovered
scientists accelerate charged particles and cause them to collide with protons, causing them to break apart. (this is done in particle accelerators)
the even smaller particles that scientists suspect protons and neutrons to be composed of
quarks
particles with an electric charge of 1-
electrons
electrically neutral particles in the nucleus; they hvae no charge
neutrons
