化学键介绍
视频：
化学键
离子键与共价键
视频：
离子键与共价键
This
video
is
an
overview
of
chemical
bonds.
本视频是关于化学键的概述·
How
do
the
atoms
of
elements
form
chemical
bonds
元素的原子如何形成化学键呢?
Recall
that
electrons
in
an
atom
surround
the
nucleus.
回想一下,原子中的电子围绕着原子核·
They
fill
energy
levels
or
shells
in
specific
numbers.
它们以特定的数量填充能级或壳层·
Electrons
in
an
atom's
inner
shells
are
commonly
referred
to
as
core
electrons.
原子内层电子通常被称为核心电子·
Core
electrons
don't
participate
in
chemical
bonds.
核心电子不参与化学键的形成·
In
contrast
electrons
in
the
outermost
shell
of
an
atom
are
called
valence
electrons.
相比之下,原子最外层的电子被称为价电子·
Valence
electrons
do
participate
in
forming
chemical
bonds.
价电子参与形成化学键·
For
example
a
carbon
atom
with
six
protons
and
six
neutrons
in
the
nucleus
has
six
electrons.
例如,一个碳原子在原子核中有六个质子和六个中子,且有六个电子·
Notice
that
carbon
has
both
core
and
valence
electrons.
注意,碳原子既有核心电子,也有价电子·
The
innermost
shell
of
any
atom
can
hold
a
maximum
of
two
electrons
and
the
next
shell
can
hold
up
to
eight
electrons.
任何原子的最内层壳层最多可以容纳两个电子,而下一个壳层最多可以容纳八个电子·
So
two
of
the
electrons
in
carbon
fill
the
first
shell
所以,碳原子中有两个电子填满了第一层壳,
and
the
remaining
four
electrons
are
in
the
next
shell.
剩下的四个电子位于下一个壳层·
The
two
electrons
in
the
first
shell
are
carbon's
core
electrons.
第一层壳中的两个电子是碳的核心电子·
The
four
electrons
in
the
outer
shell
are
carbon's
valence
electrons.
最外层的四个电子是碳的价电子·
Atoms
with
fewer
valence
electrons
than
its
outer
shell
can
hold
aren't
as
stable
as
atoms
with
full
outer
shells.
原子的价电子数少于外层壳层可容纳的电子数时,它们的稳定性较差,而外层壳层充满电子的原子则更稳定·
However
these
atoms
can
become
more
stable
if
their
outer
shell
is
filled.
然而,如果这些原子的外层壳充满电子,它们可以变得更加稳定·
This
can
happen
either
by
losing
electrons
to
another
atom
or
attracting
electrons
from
another
atom.
这种情况可以通过将电子失去给另一个原子,或从另一个原子吸引电子来实现·
This
interaction
of
valence
electrons
between
atoms
results
in
the
formation
of
chemical
bonds.
原子之间的价电子相互作用导致了化学键的形成·
Elements
that
have
completely
filled
outer
shells
such
as
helium
are
mostly
non
reactive
那些外层壳完全填满的元素,如氦,通常是非反应性的,
which
means
they
don't
usually
form
chemical
bonds.
也就是说它们通常不会形成化学键·
Why
is
that
为什么会这样呢?
Well
it's
because
their
outer
shells
can't
accept
anymore
electrons
这是因为它们的外层壳不能再容纳更多的电子,
and
losing
all
of
their
valence
electrons
requires
too
much
energy.
而失去所有价电子需要消耗太多的能量·
There
are
two
main
types
of
chemical
bonds
化学键有两种主要类型,
they
are
ionic
bonds
一种是离子键,
when
electrons
are
transferred
from
one
atom
to
another
当电子从一个原子转移到另一个原子时形成;
and
covalent
bonds
when
atoms
share
electrons.
另一种是共价键,当原子共享电子时形成·
We'll
discuss
this
in
more
detail
separately.
我们将在后续内容中更详细地讨论这两种化学键·
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