PS 1st Semester Exam

metalloids

commonly used in computer chips & electronic devices

scientific notation

shorthand way of expressing numbers that are extremely large or small

positive

overall charge of the nucleus of an atom

Aristotle

believed that all substances were built from fire, air, water, and Earth

weight

measure of gravitational force of an object

excited state

when electrons tend to have higher amounts of energy thus becoming less stable

synthetic

elements made in lab setting

endothermic

system absorbs energy from its surroundings

valence electrons

What mainly determines periodic trends on the periodic table?

data table

simplest way to organize information from an experiment

evaporation & boiling

What are the 2 types of vaporization?

precise

measurement that is exact in amount, meaning that it is reliable or repeatable

non-metal

An unidentified element does not conduct electricity well and is a gas. What type of element is it?

plasma

What state of matter is most of the mass in the universe?

hydrogen

most abundant element in the universe

pure substance

matter that always has the same composition

time

interval between two events

density

ratio of an object's mass to its volume

Alkali

group of elements (Group 1A) have metals which are very reactive & are only found in compounds in nature

atmosphere

mixture of gases that make up the air that surrounds the Earth

isotopes of carbon

What is similar about Carbon-12 & Carbon-14?

sublimation

phase change from solid to gas (dry ice)

meteorology

study of the air that surrounds a planet

Halogens

name of group 7 on the periodic table

5

How many valence electrons are present?

family

elements with the same number of valence electrons

gas

state of matter with no definite shape or definite volume

astronomy

study of the universe beyond Earth, including the sun, moon, planets, and stars

melt

heat of fusion for water is the amount of energy needed for water to?

BEC

state of matter has atoms behaving as though they were one single particle because of the extreme low temperatures

electron

subatomic particle with negative charge

atomic number

What tells you the # of protons in one atom?

nitrogen

most abundant gas in universe

precipitate

solid that forms & separates from a liquid mixture

metalloids

elements with properties that fall between those of metals & nonmetals

Rutherford

scientist used gold foil to discover that protons are located in the center of the atom

Thomson

scientist development the "plum pudding model" stating that the atom had negative charges scattered in a cloud of positive charge

electron cloud

model that describles the most likely locations of electrons in atoms

independent variable

variable you purposely change

atoms

building blocks of all matter

supersaturated

solution that contains more solute than it would normally hold at that temperature

ductility

property allows metals to be drawn into thin wires without breaking

meter

SI unit for distance

insulator

material that resists the flow of heat

crystalline structure

particles in a solid are arranged in a regular geometric pattern

metals

properties include ductile, malleable, conductor, shiny

Noble gases

group on periodic table that is unreactive

Mendeleev

scientist arranged elements into rows in order of increasing mass so that elements with similar properties were in the same column

flammability

material's ability to burn in the presence of oxygen

vaporization

phase change in which a substance changes from a liquid to a gas

metalloid

What class is unidentified element that is found to be able to conduct electricity, but is dull?

compound

substance that is made from two or more simpler substances & can be broken down into those simpler substances

periodic table

arrangement of elements in columns, based on set of properties that repeat from row to row

hardness

physical characteristic deals with measuring how easily a material can be scratched

absolute zero

coldest an object can get in theory

vaporization

reverse of condensation

transition metals

elements that form a bridge between elements on the left & right sides of the table

carbon

organic element

isotopes

atoms of the same element that have the same number of protons, but different number of neutrons

subscripts

small #'s that tell you how many atoms of each element are present

plasma

state of matter consists of atoms being stripped of their electrons

line

Which type of graph is present in picture?

endothermic changes

melting, vaporization, sublimation

melting

phase change from solid to liquid

water

universal solvent

Democritus

first scientist to propose the idea that all atoms make up all substances

period

row in periodic table

accurate

measurement that correctly reflects the size of the thing being measured (close to the actual value)

Alkaline Earth Metals

group 2A on periodic table