2 Melting and boiling points Metals generally have high m.pt and b.pt except gallium and cesium. Non-metals have low m.pt and b.pt except diamond and graphite. 3 Density Generally high. Generally low. 4 Malleability and Ductility Malleable and ductile. Neither malleable nor ductile. 5 Electrical and thermal conductivity Good conductors of heat and electricity. Generally poor conductors of heat and electricity except graphite. 6 Luster Poses shining luster. Do not have luster except iodine. 7 Sonorous sound Give sonorous sound when struck. Does not give sonorous sound. 8 Hardness Generally hard except Na, K non-metals are generally soft except diamond. Comparison of Chemical Properties of Metals and Non-metals:- 1 Reaction with Oxygen Metal + Oxygen Metal oxide 4Na(s) + O2(g) 2Na2O(s) 4Al(s) + 3O2(g) 2Al2O3 Metals form basic oxides Zn and Al form amphoteric oxides (they show the properties of both acidic and basic oxides) Most of the metal oxides are insoluble in water Some of them dissolve to form Alkali Na2O(s) + H2O(l) 2NaOH(aq) + Oxygen Non-metal oxide C + O2 CO2 S + O2 SO2 Non-metals form acidic oxides CO and H2O are neutral oxides(they are neither acidic nor basic in nature) oxides are soluble in water They dissolve in water to form acids SO2 + H2O H2SO3 2 Reaction with water Metals with water to form metal oxides or metal hydroxide and H2 gas is released. Non-metals do not react with water, steam to evolve hydrogen gas. Because Non-metals
METALS AND NON – METALS FORMATIVE ASSESSMENT I MARKS-30 TIME- 70 MINUTES Instructions: Questions : 1 to 5 – 1 Mark each Questions : 6 to 9 – 2 each Questions : 10 to 13 – 3 Marks each Question 14 – 5 Marks metal other than mercury is liquid at room temperature? Why the item made of silver turns black when exposed to air? non – metal is lustrous? What is an amalgam?
Protection of the brain & the spinal cord- (i) Bony outer covering: skull for the brain & vertebral column for the spinal cord. (ii) Cerebrospinal fluid present in between the three membranes. Action caused by Nervous tissue Information → Nervous tissue → Brain Muscles → Causes action Path or action- impulse → Muscle cell → Changes shape due to special proteins ↓ Action caused ← Shorter form of muscles ← Change shape & arrangement of cell Chemical communication by hormones- (advantages) Electrical impulses have limitations because they reach only those cells connected to the nervous tissue. Also the nerve cells cannot generate & transmit impulses continuously. communication is slower. Hormones- (i) are chemical messengers secreted by endocrine glands (ii) Are secreted in small amounts & may act in nearby places or distant places. Do not take part in the reaction & are destroyed immediately. Hormones are secreted by- Endocrine glands & Exocrine glands S. No. Endocrine glands Exocrine glands 1. Ducts absent present 2. Secrete hormones Secrete enzymes 3. Secreted in Secreted in ducts of glands 4. Situated away from the site of action Situated near the site of action Some glands which act as both endocrine & exocrine Gland Endocrine function Exocrine function Pancreas Produces insulin & Glucagon hormone. Produces digestive enzyme. (pancreatic amylase) Testes Produces hormone Testosterone Produces male gametes (reproductive Ovaries Produces hormone Oestrogen Produces female gametes (reproductive cells) Important Endocrine glands, the hormone they secrete & their function Refer to figure 7.7 page no. 124 of N.C.E.R.T Text book) Endocrine Hormone Function Pituitary gland Growth hormone Body growth, development of & muscles (If excess- Gigantism) (If less- Dwarfism)