Read and complete the text about chemistry using the words in the box. bind charge science
nucleus interactions shape
mass particles matter
density substances amounts
ions molecules
Chemistry is the science that systematically studies the composition, properties
and activity of and various elementary forms of .
Chemistry is the study of matter and energy and interactions between them.
Energy has no or form. Matter is everything that occupies space and has
. refers to the amount of matter in a given amount of
space and is defined as the mass per unit of a substance.
The fundamental building block of matter is the atom. It has a at its
centre consisting of protons, which have a positive electrical , and neutrons
which are uncharged. Negatively charged electrons circle around nuclei. There are
super-small inside the protons and neutrons called quarks.
Chemical reactions involve between the electrons of one atom
and the electrons of another atom. Atoms which have different of
electrons and protons have positive or negative electrical charge and are called
. When atoms together, they can make larger building blocks of
matter called
- have you heard the weather forecast for today?
- they say the day will be a strong thunderstorm.
- something i can not believe. look, the sky is so clear, there is not a single cloud! and so quiet!
“don't you know that before a thunderstorm there is often a lull. i tend to believe weather forecasters.
“but weather forecasters are people too.” and people tend to make mistakes. it doesn't seem to be raining at all!
- you are a big optimist. i suppose you will remember the weather forecast when you get wet to the skin.
- and you have always been a pessimist!
- it gets very stuffy. i even breathe with difficulty.
- yes, the heat is really unbearable.
- by the way, this also indicates the approach of a thunderstorm.
вот так как то)
east or west, home is best. i believe in this proverb.
i think that my home is a little world where i can live according to my own rules. it’s because here are my relatives, my dogs, my favourite things. when i feel tired, i can relax only at home. there's no place like home. when i am ill, i feel better only at home. everything is easier at home. i like to receive guests at my home. home is most important place in the life of every person. at home we feel comfortable, calm and happy. every family holiday we celebrate at home. many days off we spend at home within the family. my dearest people live there. the furniture, the things, the pictures at home can say a lot of about their masters. masters' character, his/her habits we can learn when we look at their homes. my home is my castle – englishmen tell so. i support this. i like my home city, my motherland. my favourite place is my mother’s place of birth –the hamlet anosovo. all my childhood i spent there. there are a lot of luxurious blossoming fruit gardens. there is warm newly drawn milk of a cow or a goat. there are bright-green watery meadows. there is my lovely pond covered by duckweed. every summer i went there, but unfortunately, i don’t have time to go there now. it was the happiest time in my life when i was there. in the village near anosovo every summer celebrates holidays - the days of poetry. it’s because pushkin visited the village bolshoe boldino. when days of poetry are celebrated, famous actors’ concerts are performed there. i recollect this time with tenderness and i regret that i couldn't return these times. i would like to go there again to see my childhood place.