基本上，目标是在此代码之间有两个主要部分。 1左边的部分是所有文本，另一部分是在右边，在顶部是属性表，然后在表格图像下面。
@font-face { font-family: UbuntuG; src: url('ubuntu-fonts/Ubuntu-L.ttf'); }
body {
background-color: #1d1d1d;
}
h1 {
color: white; font-family: UbuntuG; font-size: 30;
}
h2 {
color: white; font-family: UbuntuG; font-size: 18;
}
p {
color: white; font-family: Arial; font-size: 16;
}
p_ANum {
color: white; font-family: Arial; font-size: 10; text-align: left;
}
table, th, td {
border: 1px solid #1d1d1d; border-spacing: 0; color: white; font-family: Arial; font-size: 16;
}
td {
text-align: center;
padding: 0;
height: 48px;
min-width:48px;
}
ul{
margin: 0px 0;
}
a {
display: block;
text-decoration: none;
color: white;
height:43px;
line-height:43px;
}<html>
<head>
<title>Periodic Table</title>
<meta content="??">
<link rel="stylesheet" type="text/css" href="theme.css">
<style>
table, th, td { border: 5px solid white; border-spacing: 0; color: #1d1d1d; font-family: Arial; font-size: 16; }
</style>
</head>
<body style="margin-top:20;margin-left:15%;margin-right:3%;">
<h1>Hydrogen</h1>
<div align="right">
<table><tr><h2>Atomic Properties</h2>
<td bgcolor=white><b>Atomic number</b></td>
<td bgcolor=white>1</td>
</tr><tr>
<td bgcolor=white><b>Atomic Mass</b></td>
<td bgcolor=white>1.007825 g.mol ^-1</td>
</tr><tr>
<td bgcolor=white><b>Electronegativity</b></td>
<td bgcolor=white>2.1</td>
</tr><tr>
<td bgcolor=white><b>Densitys</b></td>
<td bgcolor=white>0.0899*10 ^-3 g.cm ^-3 at 20 °C</td>
</tr><tr>
<td bgcolor=white><b>Melting Point</b></td>
<td bgcolor=white>- 259.2 °C</td>
</tr><tr>
<td bgcolor=white><b>Boiling Point</b></td>
<td bgcolor=white>- 252.8 °C</td>
</tr><tr>
<td bgcolor=white><b>Vanderwaals radius</b></td>
<td bgcolor=white>0.12 nm</td>
</tr><tr>
<td bgcolor=white><b>Ionic Radius</b></td>
<td bgcolor=white>0.208 (-1) nm</td>
</tr><tr>
<td bgcolor=white><b>Isotopes</b></td>
<td bgcolor=white>3</td>
</tr><tr>
<td bgcolor=white><b>Electronic shell</b></td>
<td bgcolor=white>1s^1</td>
</tr><tr>
<td bgcolor=white><b>Energy of first Ionisation</b></td>
<td bgcolor=white>1311 kJ.mol -1</td>
</tr><tr>
<td bgcolor=white><b>Discovered by</b></td>
<td bgcolor=white>Henry Cavendish 1766</td>
</tr>
</div>
<div align="Right">
<img src="assets/H_atomic.png">
<img src="assets/H_mainpic.png">
</div>
<span align="left">
<p>
First element in the periodic table. In normal conditions it’s a colourless, odourless and insipid gas, formed by diatomic molecules, H2. The hydrogen atom, symbol H, is formed by a nucleus with one unit of positive charge and one electron. Its atomic number is 1 and its atomic weight 1,00797 g/mol. It’s one of the main compounds of water and of all organic matter, and it’s widely spread not only in The Earth but also in the entire Universe. There are three hydrogen isotopes: protium, mass 1, found in more than 99,985% of the natural element; deuterium, mass 2, found in nature in 0.015% approximately, and tritium, mass 3, which appears in small quantities in nature, but can be artificially produced by various nuclear reactions.
Uses: The most important use of hydrogen is the ammonia synthesis. The use of hydrogen is extending quickly in fuel refinement, like the breaking down by hydrogen (hydrocracking), and in sulphur elimination. Huge quantities of hydrogen are consumed in the catalytic hydrogenation of unsaturated vegetable oils to obtain solid fat. Hydrogenation is used in the manufacture of organic chemical products. Huge quantities of hydrogen are used as rocket fuels, in combination with oxygen or fluor, and as a rocket propellent propelled by nuclear energy.
Hydrogen can be burned in internal combustion engines. Hydrogen fuel cells are being looked into as a way to provide power and research is being conducted on hydrogen as a possible major future fuel. For instance it can be converted to and from electricity from bio-fuels, from and into natural gas and diesel fuel, theoretically with no emissions of either CO2 or toxic chemicals.
Properties: Common hydrogen has a molecular weight of 2,01594 g. As a gas it has a density of 0.071 g/l at 0ºC and 1 atm. Its relative density, compared with that of the air, is 0.0695. Hydrogen is the most flammable of all the known substances. Hydrogen is slightly more soluble in organic solvents than in water. Many metals absorb hydrogen. Hydrogen absorption by steel can result in brittle steel, which leads to fails in the chemical process equipment.
At normal temperature hydrogen is a not very reactive substance, unless it has been activated somehow; for instance, by an appropriate catalyser. At high temperatures it’s highly reactive.
Although in general it’s diatomic, molecular hydrogen dissociates into free atoms at high temperatures. Atomic hydrogen is a powerful reductive agent, even at ambient temperature. It reacts with the oxides and chlorides of many metals, like silver, copper, lead, bismuth and mercury, to produce free metals. It reduces some salts to their metallic state, like nitrates, nitrites and sodium and potassium cyanide. It reacts with a number of elements, metals and non-metals, to produce hydrides, like NAH, KH, H2S and PH3. Atomic hydrogen produces hydrogen peroxide, H2O2, with oxygen.
Atomic hydrogen reacts with organic compounds to form a complex mixture of products; with etilene, C2H4, for instance, the products are ethane, C2H6, and butane, C4H10. The heat released when the hydrogen atoms recombine to form the hydrogen molecules is used to obtain high temperatures in atomic hydrogen welding.
Hydrogen reacts with oxygen to form water and this reaction is extraordinarily slow at ambient temperature; but if it’s accelerated by a catalyser, like platinum, or an electric spark, it’s made with explosive violence.
</p>
</span>
</body>
</html>
答案 0 :(得分：1)
第一个问题是您不要在要彼此相邻显示的元素上使用ID或类。这使得CSS很难定位。我会通过添加课程.left和.right来解决这个问题。
下一个问题是您忘记关闭<table>标记了。我把它固定在提供的小提琴中。
第三个问题是，您的表格单元格同时具有background-color和color white，这使得它们非常难以阅读。您最初没有注意到这一点，因为您缺少表格的结束标记（这意味着样式未应用于它）。您可以通过将背景颜色或颜色更改为黑色来解决此问题：
td {
color: #000;
}
第四个问题是你真的想要移动你的图像，以便它们包含在与表相同的容器中，以便浮动按预期工作......
而不是：
</tr>
</div>
<div align="Right">
<img src="assets/H_atomic.png">
<img src="assets/H_mainpic.png">
</div>
只需使用：
</tr>
<img src="assets/H_atomic.png">
<img src="assets/H_mainpic.png">
</div>
我已经解决了这个问题。
现在修复了代码，为了使组件按照你想要的方式显示，你需要给它们一个宽度，然后将它们浮动到左边，如下：
.left, .right {
float: right;
width: 46%;
padding: 2%;
}
有关工作示例，请参阅this fiddle。
希望这有帮助！ ：）