The Difference Between an Element Group and Period

The Difference Between an Element Group and Period Groups and periods are two ways of categorizing elements in the periodic table. Periods are horizontal rows (across) the periodic table, while groups are vertical columns (down) the table. Atomic number increases as you move down a group or across a period. Element Groups Elements in a group share a common number of valence electrons. For example, all of the elements in the alkaline earth group have a valence of two. Elements belonging to a group typically share several common properties. The groups in the periodic table go by a variety of different names: IUPAC Name Common Name Family Old IUPAC CAS notes Group 1 alkali metals lithium family IA IA excluding hydrogen Group 2 alkaline earth metals beryllium family IIA IIA Group 3 scandium family IIIA IIIB Group 4 titanium family IVA IVB Group 5 vanadium family VA VB Group 6 chromium family VIA VIB Group 7 manganese family VIIA VIIB Group 8 iron family VIII VIIIB Group 9 cobalt family VIII VIIIB Group 10 nickel family VIII VIIIB Group 11 coinage metals copper family IB IB Group 12 volatile metals zinc family IIB IIB Group 13 icoasagens boron family IIIB IIIA Group 14 tetrels, crystallogens carbon family IVB IVA tetrels from the Greek tetra for four Group 15 pentels, pnictogens nitrogen family VB VA pentels from the Greek penta for five Group 16 chalcogens oxygen family VIB VIA Group 17 halogens fluorine family VIIB VIIA Group 18 noble gases, aerogens helium family or neon family Group 0 VIIIA Another way to group elements is based on their shared properties (in some cases, these groupings do not correspond to the columns in the periodic table). Such groups include  alkali metals, alkaline earth metals, transition metals (including  rare earth elements or lanthanides and also actinides), basic metals, metalloids or semimetals, nonmetals, halogens, and noble gases. Within  this classification system, hydrogen is a nonmetal. The nonmetals, halogens, and noble gases are all types of nonmetallic elements. The metalloids have intermediate properties. All of the other elements are metallic. Element Periods Elements in a period share the highest unexcited electron energy level. There are more elements in some periods than others because the number of elements is determined by the number of electrons allowed in each energy sub-level. There are seven  periods for naturally occurring elements: Period 1: H, He (does not follow the octet rule)Period 2: Li, Be, B, C, N, O, F, Ne (involves s and p orbitals)Period 3: Na, Mg, Al, Si, P, S, Cl, Ar (all have at least 1 stable isotope)Period 4: K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr (first period with d-block elements)Period 5: Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sn, Te, I, Xe (same number of elements as period 4, same general structure, and includes first exclusively radioactive element, Tc)Period 6: Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn (first period with f-block elements)Period 7: Fr, Ra, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rd, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, Uut, Fl, Uup, Lv, Uus, Uuo (all elements are radioactive; contains heaviest natural elements)

Towton - Battle of Towton - Wars of the Roses - Edward IV

Towton - Battle of Towton - Wars of the Roses - Edward IV Battle of Towton: Date Conflict: The Battle of Towton was fought on March 29, 1461, during the Wars of the Roses (1455-1485). Armies Commanders Yorkists Edward IV20,000-36,000 men Lancastrians Henry Beaufort, Duke of Somerset25,000-42,000 men Battle of Towton - Background: Beginning in 1455, the Wars of the Roses saw a dynastic conflict erupt between King Henry VI (Lancastrians) and the out-of-favor Richard, Duke of York (Yorkists). Prone to bouts of insanity, Henrys cause was chiefly advocated by his wife, Margaret of Anjou, who sought to protect their sons, Edward of Westminster, birthright. In 1460, the fighting escalated with Yorkist forces winning the Battle of Northampton and capturing Henry. Seeking to assert his power, Richard attempted to claim the throne after the victory. Blocked from this by his supporters, he agreed to the Act of Accord which disinherited Henrys son and stated that Richard would ascend to the throne upon the kings death. Unwilling to let this stand, Margaret raised an army in northern England to revive the Lancastrian cause. Marching north in late 1460, Richard was defeated and killed at the Battle of Wakefield. Moving south, Margarets army defeated the Earl of Warwick at the Second Battle of St. Albans and recovered Henry. Advancing on London, her army was prevented from entering the city by the Council of London which feared looting. Battle of Towton - A King Made: As Henry was unwilling to enter the city by force, negotiations began between Margaret and the council. During this time, she learned that Richards son, Edward, Earl of March, had defeated Lancastrian forces near the Welsh border at Mortimers Cross and was uniting with the remnants of Warwicks army. Concerned about this threat to their rear, the Lancastrian army began withdrawing northwards to a defensible line along the River Aire. From here they could safely await reinforcements from the north. A skillful politician, Warwick brought Edward to London and on March 4 had him crowned as King Edward IV. Battle of Towton - Initial Encounters: Seeking to defend his newly won crown, Edward immediately began moving to crush the Lancastrian forces in the north. Departing on March 11, the army marched north in three divisions under the command of Warwick, Lord Fauconberg, and Edward. In addition, John Mowbry, Duke of Norfolk, was sent to the eastern counties to raise additional troops. As the Yorkists advanced, Henry Beaufort, Duke of Somerset, commanding the Lancastrian army began making preparations for battle. Leaving Henry, Margaret, and Prince Edward at York, he deployed his forces between the villages of Saxton and Towton. On March 28, 500 Lancastrians under John Neville and Lord Clifford attacked a Yorkist detachment at Ferrybridge. Overwhelming men under Lord Fitzwater, they secured the bridge over the Aire. Learning of this, Edward organized a counterattack and sent Warwick to attack Ferrybridge. To support this advance, Fauconberg was ordered to cross the river four miles upstream at Castleford and move to attack Cliffords right flank. While Warwicks assault was largely held, Clifford was forced to fall back when Fauconberg arrived. In a running fight, the Lancastrians were defeated and Clifford was killed near Dinting Dale. Battle of Towton - Battle Joined: The crossing retaken, Edward advanced across the river the next morning, Palm Sunday, despite the fact that Norfolk still had not arrived. Aware of the previous days defeat, Somerset deployed the Lancastrian army on a high plateau with its right anchored on the stream of the Cock Beck. Though the Lancastrians occupied a strong a position and had a numerical advantage, the weather worked against them as the wind was in their face. A snowy day, this blew the snow in their eyes and limited visibility. Forming to the south, the veteran Fauconberg advanced his archers and opened fire. Assisted by the strong the wind, the Yorkist arrows fell in the Lancastrian ranks causing casualties. Replying, the Lancastrian archers arrows were hampered by the wind and fell short of the enemys line. Unable to see this due to the weather, they emptied their quivers to no effect. Again the Yorkist archers advanced, gathering up the Lancastrian arrows and shooting them back. With losses mounting, Somerset was forced to take action and ordered his troops forward with a cry of King Henry! Slamming into the Yorkist line, they slowly began pushing them back (Map). On the Lancastrian right, Somersets cavalry succeeded in driving off its opposite number, but the threat was contained when Edward shifted troops block their advance. Details pertaining the fighting are scarce, but it is known that Edward flew about the field encouraging his men to hold and fight. As the battle raged, the weather worsened and several impromptu truces were called to clear the dead and wounded from between the lines. With his army under severe pressure, Edwards fortunes were bolstered when Norfolk arrived after noon. Joining Edwards right, his fresh troops slowly began to turn the battle. Outflanked by the new arrivals, Somerset shifted troops from his right and center to meet the threat. As the fighting continued, Norfolks men began to push back the Lancastrian right as Somersets men tired. Finally as their line neared Towton Dale, it broke and with it the entire Lancastrian army. Collapsing into full retreat, they fled north in an attempt to cross the Cock Beck. In full pursuit, Edwards men inflicted severe losses on the retreating Lancastrians. At the river a small timber bridge quickly collapsed and others reportedly crossed on a bridge of bodies. Sending horsemen forward, Edward pursued the fleeing soldiers through the night as the remnants of Somersets army retreated to York. Battle of Towton - Aftermath: Casualties for the Battle of Towton are not known with any precision though some sources indicate they may have been has high as 28,000 total. Others estimate losses around 20,000 with 15,000 for Somerset and 5,000 for Edward. The largest battle fought in Britain, Towton was a decisive victory for Edward and effectively secured his crown. Abandoning York, Henry and Margaret fled north to Scotland before separating with the latter ultimately going to France to seek aid. Though some fighting continued for the next decade, Edward ruled in relative peace until the Readeption of Henry VI in 1470. Selected Sources HistoryNet: Battle of TowtonUK Battlfields Resource Centre: Battle of Towton