trends across the periodic table — HSC chemistry year 11, live

Trends across the periodic table

Almost every trend on the periodic table comes back to one tug-of-war: how hard the nucleus pulls on the outermost electrons. Across a period, protons are added but the electrons go into the same shell, so the pull strengthens and atoms shrink, hold their electrons harder and attract shared electrons more strongly. Down a group, each new shell puts the outer electrons further out behind more shielding, so atoms grow, give electrons up more easily and, for metals, react faster with water. This is the real knowscape from knowhere, not a picture of one. Drag it. Watch what actually changes.

chemistry · reactive chemistry · trends across the periodic tabledrag it · it is yours

why this one carries the topic.

Every reaction here is atoms swapping partners: none made, none lost, so every equation balances. The rest is two questions: in redox, who gives up electrons (whoever holds them loosest), and how fast it goes (only collisions with enough energy, aimed right, count).

A main-group periodic table (periods 1 to 6) recoloured by atomic radius, first ionisation energy, electronegativity, state at 25 °C or reactivity with water, where you can step through the elements and see a bar chart of the trend across the selected period or down its group.

five things, not forty.

Across a period core charge (effective nuclear charge) rises while the outer shell stays the same, so atomic radius shrinks; down a group each extra shell makes atoms larger.

First ionisation energy and electronegativity rise across a period and fall down a group, because a closer, less-shielded outer electron is held more tightly.

Metal activity tracks how easily outer electrons are lost: group 1 and 2 reactivity with water climbs down each group as radius grows and ionisation energy and electronegativity fall.

Period number matches the number of occupied shells and group number sets the outer electrons, so shell (2,8,1) and subshell (1s² 2s² 2p⁶ 3s¹) configurations predict an element's place.

Metallic character falls across a period and rises down a group: metals sit left, metalloids along the staircase, non-metals right, and the elements that are gases at room temperature cluster top right.

nothing here is a standalone fact.

knowhere maps every concept to what it rests on and what rests on it — 2 underneath this one, 4 built on top. Each one says why, in a sentence, not as an arrow on a diagram.

this concepttrends across the periodic tableA main-group periodic table (periods 1 to 6) recoloured by atomic radius, first ionisation energy, electronegativity, state at 25 °C or reactivity with water, where you can step through the elements and see a bar chart of the trend across the selected period or down its group.

sits under itprotons, neutrons and isotopesbecause Core charge starts with counting protons in the nucleus and electrons around it.

sits under itelectron shells filling upbecause Every trend is explained by shells and subshells, so students need to write electron configurations first.

built on italpha, beta and gamma decaybecause Naming the daughter means finding the element with the new atomic number on the periodic table.

built on itionic versus covalent bondingbecause Electronegativity is a periodic trend; you need to know it rises across a period and up a group.

built on itionic, covalent and metallic structuresbecause Metal versus non-metal position predicts which structure an element or compound forms.

built on itbonds within versus forces betweenbecause Electronegativity differences explain which molecules are polar and which forces between them act.

4 more, same treatment.

Each one is its own knowscape in the app — built for how a particular student takes things in, not one explanation handed to everybody.

balancing equations atom by atomin the appsix reaction types and what they makein the appmetal activity serieslive →oxidation numbers: tracking the electronsin the app

they don't read it. they run it.

Every HSC and VCE concept in knowhere is built like this one — mapped to your curriculum, never capped by it. Free for a week. No lock-in, cancel inside the week and pay nothing.

Free for a week, then a plan you can stop any time.

not your card? send it to whoever's is.