Chem Lap 2 Quiz

Anything that has mass and takes up space is called ____

Matter

A type of matter with a fixed composition and consistent properties is called a _____

pure substance

A combination of two or more substances that are physically combined is called a ________

mixture

A pure substance that contains only one type of atom is called an______

element

A pure substance made of two or more different elements chemically bonded together is called a _______

compound

A mixture that has a uniform composition throughout is called a _______ mixture

homogeneous

A mixture that has a non-uniform composition with visibly different parts is called a _________ mixture

heterogeneous

Elements and compounds are both examples of __________

pure substances

Salt water is an example of a ____________ mixture because the salt is evenly distributed throughout the water.

homogeneous

A mixture of sand and water is an example of a __________ mixture because of its composition is not uniform

heterogeneous

____________ proposed that matter is made of tiny indivisible particles called atomos

Democritus

___________ believed that matter was continuous and could not be divided indefinitely. He also supported the idea that matter consisted of four basic elements: earth, water, air, and fire

Aristotle

_________ developed the first modern atomic theory and proposed that matter ismade of atoms

Dalton

__________ discovered the electron through experiments with cathode rays

J.J. Thomson

__________ proposed the "plum pudding"model, in which electrons were embedded in a positively charged sphere

J.J. Thomson

___________ conducted the gold foil experiment and concluded that atoms contain a small dense and positively charged nucleus

Rutherford

___________ discovered the neutron a particle found in the nucleus with no electrical charge

Chadwick

____________ proposed that electrons occupy specific energy levels around the nucleus

Bohr

___________ developed the quantum mechanical model of the atom describing electrons in terms of probability distributions rather than fixed paths

Shrödinger

Which scientist's experiment showed that most of the atom is empty space?

Ernest Rutherford

Which scientist's model included electrons embedded in a positively charged sphere?

J.J. Thomson

Which scientist proposed that electrons occupy specific energy levels?

Niels Bohr

Which two scientists had opposing views about whether matter was made of tiny particles or was continuous?

Dalton and Rutherford

Which scientist developed the modern quantum mechanical model of the atom?

Edwin Shrödinger

Difference between element and compound?

elemtent 1 type of atom compound 2 or more different elements (chemically bonded)

Difference between homogeneous and heterogeneous mixutre?

homogeneous uniform composition, heterogeneous non uniform composition

The electrode that produces the stream of electrons in a cathode ray tube is called the __________

cathode

The electrode that attracts electrons is called the _______

anode

Thomson discovered that cathode rays were made of tiny particles with a _________ charge

negative

Thomsons experiments demonstrated that atoms contain smaller particles called __________

electrons

Thomsons work helped scientists determine that atoms contain particles with a very small _______ compared with the entire atom.

mass

Rutherford directed _______________ at a very thin sheet of ______ _______.

alpha particles, gold foil

Most of the alpha particles passed straight through the foil, suggesting that atoms are mostly ___________.

Empty space

A small number of alpha particles were strongly __________ or bounced back

deflected

Rutherford concluded that atoms contain a small, dense_________.

nucleus

Because alpha particles are positively charged, their deflection suggested the nucleus is also ____________ charged

positively

Chadwick bombarded _____________ with alpha particles producing a penetrating form of radiation

beryllium

Chadwick directed this radiation at ______________ which caused protons to be ejected

paraffin wax

Chadwick concluded that the radiation consisted of particles with approximately the mass of a proton but no electrical charge. These particles were called ___________-

neutrons

A neutron has no electrical charge, meaning it is electrically ____________

neutral

Neutrons are located in the atomic __________ along with protons

nucleus

Why was the discovery of the neutron important for understanding atomic structure?

The discovery of the neutron helped explain atomic mass and showed that the nucleus contains both protons and neutrons

Which scientist discovered the electron? ______

J.J. Thomson

Which scientist provided evidence for a small, dense nucleus? _________

Ernest Rutherford

Which scientist discovered the neutron?_________

James Chadwick

Cathode Ray Tube

atoms have negatively charged particles called electrons

Gold Foil Experiment

atoms are mostly empty space, with a tiny, positively charged, dense nucleus

Neutron detection experiment

nucleus contains neutral particles called neutrons with mass equal to protons

Explain how these three experiments changed scientists' understanding of the atom.

These experiments changed the atomic model by showing that atoms are divisible and contain smaller particles. Thomson discovered electrons, demonstrating that atoms contain negatively charged particles. Rutherford showed that atoms are mostly empty space with a small, dense, positively charged nucleus. Chadwick discovered neutrons, establishing that the nucleus contains both protons and neutrons. Together, these discoveries led to a more accurate understanding of atomic structure.

Still learning (40)

You've started learning these terms. Keep it up!