Atomic Models
Who proposed the "plum pudding" model of the atom?
J.J. Thomson
Which subatomic particle has a negative charge?
Electron
What is the Periodic Table primarily organized by?
Atomic number
What does it mean if a metal is malleable?
It can be hammered into thin sheets
What is the atomic number of an atom with 6 protons?
6
What did Rutherford’s gold foil experiment reveal about the atom?
That atoms are mostly empty space with a small, dense, positively charged nucleus
Where in the atom are protons and neutrons located?
In the nucleus
What do all elements in the same group have in common?
Same number of valence electrons
Which metal is a liquid at room temperature?
Mercury
What is the mass number of an atom with 8 protons and 8 neutrons?
16
How did Bohr improve upon Rutherford’s model?
He introduced fixed orbits (energy levels) for electrons around the nucleus
Which subatomic particle has the smallest mass?
Electron
Which group contains the noble gases, and what is their key trait?
Group 18; they are very stable and unreactive
What makes metals good conductors of electricity?
They have free-moving (delocalized) electrons
What is an isotope? Give an example.
Atoms of the same element with different numbers of neutrons; e.g., Carbon-12 and Carbon-14
What is the key difference between Bohr’s model and the modern cloud model?
Bohr’s model has electrons in fixed paths; the cloud model shows electrons in probabilistic regions (clouds)
What is the mass number of an atom with 17 protons and 18 neutrons?
35
Why do elements in the same period have different reactivities even though they have the same number of shells?
They have different numbers of valence electrons, which affects reactivity
Compare the reactivity of Group 1 and Group 2 metals.
Group 1 metals are more reactive, especially with water
Fill in the missing info: Neon, Atomic Number: 10, Mass Number: 21 → Neutrons = ?
11 neutrons
Describe one flaw in Dalton’s atomic theory using modern knowledge.
Dalton thought atoms were indivisible, but we now know atoms are made of subatomic particles
An atom has 15 protons, 15 electrons, and 17 neutrons. Name the isotope and say if it's neutral or charged.
Phosphorus-32, and it is neutral because protons = electrons
Why do chemical properties repeat in a pattern across periods even as atomic number increases?
Because the number of valence electrons repeats, causing periodic properties to recur
Give two differences between transition metals and alkali metals.
Transition metals form colored compounds and have variable charges; alkali metals are softer and react explosively with water
Magnesium has 3 isotopes: Mg-24 (79%), Mg-25 (10%), Mg-26 (11%). What does this suggest about magnesium’s average atomic mass?
The average mass will be closest to 24 because Mg-24 is the most abundant