Physical Science 1 Flashcards
Who proposed that atoms are the smallest unit of an element
Dalton
What are atomic compounds formed of
Atoms combine in fixed ratios to form compounds
What did the cathode ray experiment created by JJ Thompson result in
Negatively charged particles, electrons
What is the plum pudding model of the atom
A positively charged sphere with negatively charged electrons embedded within it
What was the result of Rutherford’s gold foil experiment
Protons
Do Protons contain a positive or negative charge
Positive, negative is for Electrons
James Chadwick’s experiment wherein he bombarded beryllium with alpha particles caused what discovery
The discovery of neutrons
What role do neutrons play in atomic stability
Neutrons stabilize the nucleus of an atom by providing a strong nuclear force that binds protons together
Who proposed that electrons orbit the nucleus of an aton in specific energy levels
Niels Bohr
What is an alpha particle
2 protons and 2 electrons in an atom
What is alpha decay
The emission of alpha particle from an atom’s nucleus
What is the penetration ability of alpha decay
Low, it can be stopped by paper or skin
What is beta decay
The emission of an electron (beta particle) from an atom’s nucelus
What is beta decay’s penetration ability
Moderate, it can be stopped by aluminum foil or wood
What is Gamma decay
The emission of high energy electromagnetic radiation from an excited nucleus
What is Gamma decay’s penetration level
High it can be stopped by iron, lead, and other thick metal plates
What machine smashes atoms together at high speeds to create new elements
Particle accelerator
What are intermolecular forces
Attractive forces between molecules that hold atoms in the molecule together
What is the intermolecular force which occurs between polar molecules
dipole-dipole forces
What strong intermolecular force occurs when hydrogen bond to a highly electronegative element
Hydrogen bonding
What type of intermolecular force is present in all molecules with the weakest IMF but can increase strength with more electrons and more surface area
London dispersion forces
If a molecule is nonpolar what intermolecular force are present
London dispersion forces are present
Why do polar substances dissolve in polar solvents
Because of dipole dipole or hydrogen bonding
Why do non polar substances dissolve in non polar solvents
Due to london dispersion
Why is it that higher IMF makes the boiling/melting point of a substance higher
More energy is needed to seperate the molecules
Why do stronger IMFs lead to higher surface tension
Molecules at the surface are held more tightly
Why do substances with stronger IMFs have higher viscosity
Molecules are stickier and do not move past each other as easily leading to higher viscosity
