Ch 3 and 4 Review Flashcards
A is generally a poor conductor of heat and electricity. It has a wide range of chemical properties. A also tends to gain electrons. A is
a nonmetal
Blimps were once filled using hydrogen, but now helium is used instead. Why is helium a better choice than hydrogen?
Hydrogen is flammable, helium isn’t
Which particles account for nearly all of the mass of the atom?
protons and neutrons
All the elements in the family have the:
Same number of valence electrons
The plum pudding model of an atom was proposed by
J.J. Thomson
Across a period, the effective nuclear charge increases and therefore it becomes ____ to remove an electron.
Harder
Where are neutrons located?
In the nucleus, along with protons
Who discovered the nucleus of the atom?
Ernest Rutherford
T/F Mass is always conserved in chemical reactions
True
What happens when an electron is removed from an atom?
A positive charge remains
The second series of inner transition elements are called…
actinides
What is a correct explanation of the Plum Pudding model?
The protons are the pudding and the electrons are scattered like pieces of plum.
Dalton believed that atoms are
Tiny, indestructible, and indivisible
Which scientist discovered the electron?
J.J. Thomson
The mass of a neutron is close to the mass of…
the nucleus
T/F The outer electrons shield the inner electrons from the positive charge of the nucleus
False, It’s the opposite
Periods are…
Horizontal
Groups are…
Vertical
What is the only nonmetal that is liquid at room temperature?
Bromine
T/F The nucleus is a positively charged region at the center of an atom, which consists of protons and electrons
True
The first series of inner transition elements are called…
lanthanides
Nonmetals have ____ ionization and ____ electronegativity
high, high
What’s the purpose of the stairs in the periodic table?
To separate nonmetals and metals, also to distinguish the transition metals.
_____ are poor conductors of electricity
nonmetals
Who created the Periodic Table?
Dmitri Mendeleev
T/F Halogens are gases at room temperature
false
How many periods in the periodic table?
7
How many families in the periodic table?
18
T/F Mendeleev used atomic numbers to organize his table
False, the nucleus hadn’t been discovered yet
What is electronegativity?
A chemical property that exhbibits periodicity
Why do noble gases rarely form ions?
Noble gases don’t form compounds, the noble gases are already complete.
Draw Dalton’s Atom
It should be a solid sphere
What are Isotopes?
Atoms of the same element with different numbers of neutrons and the same number of protons.
Metals are the ones who usually ____ electrons
lose
What is group 1 called and what’s their charge? How many electrons do they gain/lose?
Alkali metals, positive charge, lose 1 electron
What is group 2 called and what’s their charge? How many electrons do they gain/lose??
Alkaline earth metals, positive charge, loses 2 electrons
What are groups 3-12?
Transition metals
