Chemistery

You can't count molecules, but you can weigh them — and molar mass is the bridge between the two. It's the single most-used number in chemistry calculations, and it's read straight off a periodic table you already have. The short answer: molar mass is the mass of one mole of a substance, measured in grams per mole (g/mol) . Numerically it equals the substance's atomic or formula mass, so you find it by adding up the atomic masses of every atom in the formula. What molar mass actually means A mole is 6.022 × 10²³ particles. Molar mass answers the practical follow-up: what does that pile weigh? The periodic table tells you carbon's atomic mass is 12.011 . That means one mole of carbon atoms weighs 12.011 g . Oxygen's is 15.999, so a mole of oxygen atoms weighs 15.999 g. The system was built so those two numbers always match — no conversion factor, no extra step. Think of it like a price list. If eggs cost $3 per dozen, "per dozen" is your conversi...

When two atoms share electrons in a bond, the sharing is rarely fair. One atom almost always pulls harder than the other. Electronegativity is the number that captures that pull — and it quietly decides whether a bond turns out ionic, polar, or perfectly even. The short answer: electronegativity is a measure of how strongly an atom attracts the shared electrons in a chemical bond. The higher an atom's electronegativity, the harder it tugs the bonding electrons toward itself. What electronegativity actually measures Picture a chemical bond as a tug-of-war over a pair of electrons. Electronegativity tells you how strong each atom is in that contest. A highly electronegative atom (like fluorine or oxygen) pulls the shared electrons close. A weakly electronegative atom (like sodium) barely pulls at all and tends to lose the electrons outright. Chemists put this on a scale called the Pauling scale , running from about 0.7 up to 3.98: Fluorine (F) = 3.98 — the most electronega...

Look at a periodic table and most of it is metals — but the small patch of nonmetals on the right side includes oxygen, carbon, and nitrogen, the elements life is made of. Telling the two groups apart is one of the first skills that makes the periodic table feel readable. The short answer: metals tend to be shiny, conduct electricity, bend without breaking, and lose electrons. Nonmetals tend to be dull, don't conduct, are brittle when solid, and gain or share electrons. On the periodic table, a zig-zag staircase line separates the metals (left and centre) from the nonmetals (upper right). Quick comparison at a glance Feature Metals Nonmetals Position on the table Left and centre (most of it) Upper right Appearance Shiny (lustrous) Dull Electrical/heat conductivity Good conductors Poor (insulators) When solid Malleable & ductile (bend, stretch) Brittle (shatter) State at room temperature Mostly solid (mercury is liquid) Gases, liquids, or ...