Examples of the chemical bonding in covalent and ionic halogen compounds are described with electron configurations and dot & cross diagrams and structural formulae and molecular shapes. PLEASE NOTE KS4 Science GCSE/IGCSE/O Level GROUP 7 HALOGENS NOTES are on a separate webpage.
Causes. Urinary tract infections typically occur when bacteria enter the urinary tract through the urethra and begin to multiply in the bladder. Although the urinary system is designed to keep out such microscopic invaders, these defenses sometimes fail.he most common UTIs occur mainly in women and affect the bladder and urethra. 1  Infection of the bladder (cystitis). 2  Infection of the urethra (urethritis). 3  Symptoms. 4  Risk factors.
Infections. Urinary tract infections (UTIs) are one of the leading causes of painful urination. Infections can occur in any part of the urinary tract, including: 1  Kidneys. 2  Ureters (tubes that carry urine from the kidneys to the bladder). 3  Bladder.